A backflow preventer is a necessary part of an irrigation system that helps make sure that the water in the pipes only flows in one direction, rather than backing up and going in the reverse direction.
What does a backflow preventer do?
Think of the backflow preventer like a gate or a turnstile at the subway station or amusement park. You can walk through, but if you try to turn around and go back you will find that you are out of luck. There is a barrier that prevents you from reversing course and returning the way that you came.
The same rules apply with backflow prevention. If a back siphon forms and the water in your pipes starts to reverse course, a backflow valve helps to keep the water from reversing course and going in the opposite direction back into your home’s drinking water pipes through a back siphon.
DISCLAIMER: This information on this site is for entertainment purposes only. The authors and owners of this site accept no responsibility or liability for any actions taken by readers. If you are not comfortable attempting repairs, please hire a licensed professional. Thank you!
Let’s say that you (or one of your neighbors) fertilize your yard or apply pesticides to your lawn, you do not want the fertilizer and pesticides pooling around your sprinkler heads, flowing down through the nozzles in your irrigation system, and mixing with your drinking water.
This is why your irrigation system has a backflow valve. It lets water run from your pipes out to the sprinkler system, but prevents it from re-entering your pipes through a back siphon by using check valves, and sometimes vents in some backflow preventer types.
There are many different backflow preventer types. In order to choose the correct backflow preventer type that your municipality requires, your town, city, county, or whatever governing body should be able to provide you with helpful resources. This article is a general overview not guidance for your specific municipality’s laws or statutes.
If you want to be certain that you are buying and installing the correct backflow preventer type, please check with your municipality or consult with an irrigation company or a licensed backflow tester (more information about testers below) in your area. They should hopefully be able to provide you with specific information to help you make the best decision possible for the various backflow preventer types for your home.
Contaminants
If there is any possibility of water contamination, it is wise to spend the necessary money to invest in a backflow preventer that will help prevent pollutants of water from entering your pipes. You want to ensure that your drinking water is safe. Saving money sure is nice, but it is not a good idea to cut costs when it comes to safe drinking water for you and your family.
What is Cross Connection?
Cross connection is the point in plumbing lines where a non potable water line connects to a potable water line for non-drinking applications such as a hose bib, irrigation system, or fire sprinklers.
When we talk about cross connection for an irrigation system we mean the “point of connection” or the place where the irrigation mainline begins. This is generally a pipe tee that connects to the potable water line, then some pipe, and then a shut-off valve.
Somewhere down the line from the sprinkler shut-off valve is where the backflow preventer would be installed to prevent contaminants from entering the potable water lines in your house.
Backflow Preventer Types
What kind of backflow preventer do I have?
Great question! There are all different kinds of backflow valves. We will go over some different categories below.
Dual Check Backflow Preventer
A dual check valve is a basic, low-priced backflow preventer for residential irrigation systems. A dual check backflow preventer has two separate, spring-loaded valves that prevent water from flowing backward into the drinking supply. The idea is that each of the valves are redundant; so if one check valve fails, the other still works to prevent contaminants from getting into the potable water lines.
A dual check valve backflow preventer is inexpensive because it is a more basic design and has fewer parts than the RPZ backflow preventer and PVB pressure vacuum breaker. Dual check valves do not have shut-off valves or test cocks.
The biggest shortcoming of a dual check backflow preventer is that it is difficult to know whether they are functioning properly because they can’t be tested, and they don’t leak.
Other types of backflow preventers have vents that will leak if there are internal problems with the backflow. When it leaks, you know there are problems. And then you can fix the problems if you know about them.
The Watts dual check valve is one of the most common kind of dual check valve device that is installed for residential irrigation systems. Though, many municipalities are now requiring RPZ backflow preventers and pressure vacuum breaker backflow preventers.
Double Check Valve
A double check valve is a lot like a dual check valve backflow preventer. Both have two independent spring-loaded valves that prevent backflow and contamination of the potable water pipes. Double check valves are more sophisticated than dual check valves because they have shut-off valves and test cocks.
Single Check Valve
A single check valve is like a dual check backflow preventer, but only has a single check valve, so there is no redundancy. A single check valve is not advisable for an irrigation system or other cross connection, as there is no backup if one of the check valves fails. A dual check valve backflow preventer is probably the minimum that should be used in most situations where the goal is to prevent water from flowing backward into your potable water supply.
Single check valves are probably not going to fulfill any municipality’s requirements for preventing water contamination. A single check valve would probably work best where the goal is to prevent backflow between two different potable water sources.
Pressure Vacuum Breaker
A pressure vacuum breaker or PVB is a better option than a dual check valve in most applications. A pressure vacuum breaker PVB valve has a spring-loaded check valve called a poppet that helps prevent water from contaminating the drinking supply if back-siphon occurs.
PVB pressure vacuum breakers also have many beneficial features that a dual check backflow preventer lacks, such as shut-off valves, test cocks, and a vent.
PVB
The shut-off valves can be extremely helpful in the event of a leak to quickly get the water off. The vent allows water to drain out of the line entirely in the event of back siphon. The test cocks allow the backflow to be tested to ensure it is working as it should. Test cocks also allow the PVB backflow preventer to be drained if the temperatures drop suddenly before you can blow out sprinkler system. For more information about how to drain your backflow preventer check out this article.
Despite all of the additional helpful features that the pressure vacuum breaker has, it also has some limitations that an RPZ valve does not have.
A PVB sprinkler pressure vacuum breaker must be installed at least a foot above the highest pipe in the sprinkler system. This means it needs to be installed at the high point of the yard (assuming the irrigation pipes run throughout the whole yard).
If your yard is flat and your municipality allows PVB pressure breaker valve devices, you are a good candidate for a pressure vacuum breaker device. Or if it is being installed at the highest point in your yard, a PVB sprinkler system vacuum breaker may also be a good option for your irrigation system.
But you will want your backflow preventer to be installed as close to the very beginning of your irrigation system’s mainline pipe as possible, so this may limit your options.
You can’t just arbitrarily pick the highest point in your yard and install it there if the highest point is not also the point where you will be connecting or tying into the plumbing for the irrigation system’s water source.
If the point of connection for your irrigation system’s water is not also the highest point in your yard, you may need to spend the extra cash on an RPZ backflow preventer.
This is because an RPZ backflow preventer does not have the same height limitations that a PVB sprinkler pressure vacuum breaker does. An RPZ backflow preventer can be installed even if it is not at the highest point of the irrigated portion of the property.
Both RPZ backflow preventers and PVB pressure vacuum breakers need to be installed a foot above ground, when they are installed outside. But an RPZ reduced pressure zone assembly can generally be installed outside, one foot above the ground anywhere, with no requirements about being installed at the highest point in the yard, relative to the underground pipes used for your irrigation system.
What Does Vacuum Breaker do?
Using a spring-loaded check valve and an air vent, a PVB pressure vacuum breaker like the Wilkins 720A pressure vacuum breaker provides a barrier that helps prevent water from your irrigation system from flowing backward and mixing with your home’s potable water.
As a result, an irrigation vacuum breaker prevents or eliminates a back siphon from forming and creating a backward flow that can introduce contaminants into the potable water supply with unappetizing additives like lawn fertilizers and pesticides.
So, whether you have a Febco pressure vacuum breaker, a Wilkins 720A pressure vacuum breaker, a different Wilkins pressure vacuum breaker, or a Watts pressure vacuum breaker, they are generally all going to work in a similar way.
What is an RPZ?
A reduced pressure zone backflow preventer (RPZ) is a more complicated and expensive type of backflow preventer than the others. An RPZ reduced pressure valve is similar to double check valve, but in addition to spring loaded check valves, RPZ backflow preventers have a relief valve that drains any water trapped between the two redundant valves.
This extra venting ability makes the RPZ valve the superior valve for situations where it is critical to prevent backflow; for instance, in health applications.
RPZ Plumbing
An RPZ reduced pressure backflow preventer has ports for testing called test cocks. A backflow tester can simply hook up the testing equipment to the test cocks and take readings. This process allows one to know with certainty whether the backflow is functioning properly or not.
Spill Resistant Vacuum Breaker:
An SVB or spill resistant vacuum breaker is very similar to a pressure vacuum breaker. The priority of a PVB pressure vacuum breaker is to prevent contamination and part of that process can allow water to drain or “spill” to get the potentially contaminated water out of the pipes and away from potable drinking supply pipes.
As a result of the spill potential, a pressure vacuum breaker is generally not a good candidate for indoor installation.
Installing a PVB pressure vacuum breaker outside is often necessary, but it comes with all sorts of potential problems. A backflow preventer that is installed outside is extremely susceptible to freeze damage.
Also, because many backflow preventers, including PVB sprinkler vacuum breakers, are required to be installed a foot above ground, theft and vandalism can pose a serious problem. Especially if the backflow preventer is installed with PVC or CPVC pipes. These plastic pipes can be easily cut, kicked, pushed, or pulled to snap.
If someone breaks the pipe and grabs the backflow and runs, you will have at least two unpleasant problems. First, your backflow preventer is gone and you will need to buy a new one and have the connections redone.
And second, if the water is on to the sprinkler system at the time it is stolen or vandalized/broken, you will have a serious irrigation system leak to deal with. Irrigation mainline pipes and backflow preventers are under pressure and when the pipes break, a lot of water can be lost in a very short amount of time. This can leave you with a high water bill, a muddy mess, and a queasy feeling over all of that wasted water.
This is where the spill resistant pressure vacuum breaker can come in handy. Because of the SVB’s selling point — it doesn’t spill the way a PVB backflow does — it can be installed indoors. This prevents the possibility of freeze damage, and makes vandalism or theft extremely unlikely.
Unlike a PVB backflow preventer (which requires the vent and the check valve to act independently), an SVB is designed to allow the poppet to close prior to the opening of the check valve. So, the spill resistant vacuum breaker allows the check valve and air vent to act together to prevent water from spilling/draining.
Hose Bibb Vacuum Breaker:
A hose bibb vacuum breaker prevents water from backing up into the potable water pipes in the event that the hose creates a back siphon and reverses course.
This is a vacuum breaker designed specifically for hoses and faucets to prevent contaminants from getting in the pipes. Whether you are using your hose bibb to connect the hose and wash your car or give your dog a bath, or you are using your hose bibb as your irrigation system’s water source, contamination is possible. Using a hose bib vacuum breaker will help prevent this from happening.
If the water reverses course from a back siphon, the hose bibb vacuum breaker opens and vents the water. This prevents the back siphon from causing contaminated water from getting into the potable water lines.
Aside from some of the other limitations that we have gone over for single check valves and dual check valves such as the lack of test cocks, hose bib vacuum breakers have a big additional limitation in that they only prevent back siphon and do not prevent back pressure. As a result, additional backflow prevention protection should be used if a shut off valve is going to be used further down the line.
What Is Backflow Testing
Backflow preventers have internal gaskets, springs, and other components that can fail over time. Some municipalities or water companies require regular testing to make sure none of those internal components have worn out.
As we have established, certain kinds of backflow preventers can be tested and some cannot. You will likely know if your city or county requires you to get your backflow device tested because your municipality will generally contact you to let you know.
They may communicate this with a letter in the mail. When the deadline approaches, they will contact you to inform you of the deadline for having the test performed and the test results submitted.
They may or may not provide a list of companies that are certified to perform the necessary tests.
How to Find Backflow Testers Near Me
If your municipality does not provide a list of backflow testers along with the notice that testing is required, you can find a backflow tester on your own using one of the standard methods:
- If you already have an irrigation company that you have worked with in the past, you can reach out to them to ask if they are certified to perform Backflow Tests in your municipality.
- Ask your neighbors or local friends and family members if they have any recommendations for a trusted licensed and certified irrigation contractor.
- Consult a service like Angie’s List or NextDoor.
- Good old fashioned Google Reviews. Search for “backflow testing” and your town or city.
- Try contacting a local irrigation distributor and ask them for suggestions or a referral. They are likely to have some ideas of companies that do good work and are trustworthy.
Backflow Preventer Pipe Fitting Unions
Pipe unions are threaded fittings (PVC or brass) that can be unscrewed to allow the backflow valve to be removed temporarily. This is especially helpful in the winter when temperatures drop below freezing.
Please note that if your backflow preventer is outside, it will need to be drained, winterized, and possibly even removed prior to below freezing temperatures.
Backflow pipe unions are built into some models of backflow preventers. If pipe unions are not included in the model of the backflow preventer that you have, PVC unions or copper unions can often be added to the pipe manifold that the backflow preventer is mounted to.
Indoor backflow preventer?
Or outdoor backflow preventer?
This will depend on a number of factors.
- PVB irrigation vacuum breakers and RPZ backflow preventers can and often do leak. So, you will need to install a vent that will hopefully prevent any leaks from ruining your nice floors and wall. Rather than a PVB sprinkler system vacuum breaker, you may want to consider a Spill-Resistant Vacuum Breaker (SVB) to prevent leaking or spilling.
- If you have an outdoor backflow preventer and you live in a colder climate, you are at risk of possible freezing. But as long as you stay on top of winterizing and draining your backflow device before the temperatures get cold, freeze-damage should not be a problem.
- An outdoor backflow preventer is susceptible to vandalism or theft. When the backflow valve is totally exposed, any jabroni can walk up and break or steal it. The best solution to this (other than opting for an indoor backflow preventer, which can have its own drawbacks) is a backflow enclosure. A backflow enclosure or backflow hot box is a box that can be locked, preventing access to anyone but the key holder. Backflow enclosures have a number of benefits. They help prevent vandalism, theft, and they can also prevent freeze damage, as certain models come with heated options.
Leaking Backflow Preventer
If your backflow preventer is leaking, you may have some options other than full replacement.
Backflow preventer manufacturers sell products called backflow repair kits that allow the internal components (poppets, springs, gaskets, o-rings, etc…) of backflow valves to be replaced.
Backflow Repair Kits
This can save quite a bit of money as metal prices have risen in recent years, and the springs, poppets, and gaskets that are part of a backflow preventer repair kit can be way less expensive than an entire backflow unit.
Frozen Backflow Preventer
Unfortunately, if your backflow preventer is located outside and you or the previous owner of your house forgot or neglected to drain, blow-out, or winterize your irrigation system prior to a cold snap, and your backflow froze and cracked, you are probably out of luck and will likely need to replace the whole thing.
But, before you shell out the big bucks for a totally new backflow, make sure the crack is actually in the backflow preventer and not just in one of the shut-off valves; because the shut-off valves can be removed and replaced. The shut-off valves will likely cost significantly less than replacing the entire backflow unit.
What Does A Backflow Preventer Look Like
A picture is worth a thousand words, so here are photos and a description of each type of backflow preventer to help you determine what type of backflow preventer you have:
Wilkins Backflow Preventers
Zurn Backflow Preventers:
Wilkins 700 Backflow Preventer
The Zurn 700 is a basic dual check backflow preventer. The Wilkins 700 backflow has two redundant, spring loaded check valves to help prevent back siphon from allowing water into the potable water pipes.
The Wilkins 700 is not appropriate for health hazard applications.
The Wilkins 700 allows maximum working pressure of 175 psi (12.06 bar).
Wilkins 760
The Wilkins 760 backflow is a basic dual check backflow preventer. The Wilkins 760 has two redundant, spring loaded check valves to help prevent back siphon from allowing water into the potable water pipes. Unlike the Wilkins 700, the Wilkins 760 also has an intermediate atmospheric vent.
The Wilkins 760 is appropriate for low hazard applications.
The Wilkins 760 allows maximum working pressure of 175 psi (12.06 bar).
Wilkins 720A
The Zurn 720A is a PVB or pressure vacuum breaker. The 720A is a Zurn vacuum breaker and includes two shut off valves so that the water is able to be turned off at the backflow. The Wilkins pressure vacuum breaker also has test cocks for draining and testing. The Wilkins 720A uses a spring-loaded check valve called a poppet that can close to prevent back siphonage from reversing course and entering the potable water supply.
The Zurn 720A is appropriate for high hazard health applications, including commercial and residential irrigation settings.
The 720A allows a maximum pressure of 150 psi (10.3 bar).
Wilkins 975XL
The Wilkins Zurn 975XL is an RPZ reduced pressure valve. The 975XL has shut off valves so that the water is able to be turned off at the RPZ backflow. The 975XL backflow also has test cocks for draining and testing the Wilkins 975XL. The Wilkins 975XL has two independent, spring-loaded check valves and a vent, as well. The 975XL is available with or without unions.
The Wilkins 975XL is appropriate for high hazard health applications, and commercial, residential, and industrial settings.
The Wilkins 975XL allows maximum working pressure of 175 psi (12.06 bar).
Wilkins 375XL
The Wilkins 375XL or Zurn 375XL is an RPZ backflow preventer. The Wilkins 375 has RPZ valves that can be shut-off so that the water is able to be turned off at the ball valves on the backflow itself. The Zurn 375 backflow also has test cocks for draining and testing the Wilkins 375 RPZ. The Wilkins 375XL has two independent, spring-loaded check valves that use poppets and a vent, as well.
The Zurn 375XL functions in the same way as the more expensive Wilkins 975XL, but because it uses a plastic Wilkins 375 vessel, rather than being fully brass, the Wilkins 375 is less expensive.
The Wilkins 375XL is appropriate for high hazard applications.
The Wilkins 375XL allows maximum working pressure of 175 psi (12.06 bar).
Wilkins 950XL
The Wilkins 950XL is a double check backflow preventer. The Wilkins 950XL has shut-off valves that can be closed off so that the water is able to be turned off at the ball valves on the backflow itself. The Wilkins 950XL has two independent, spring-loaded check valves, and test cocks as well.
The Wilkins 950XL is not designed for high risk health applications. The Wilkins 950XL protects from both back siphonage and also back pressure.
The Wilkins 950XL allows maximum working pressure of 175 psi (12.06 bar).
Wilkins 460XL
The Wilkins 460XL is a spill resistant vacuum breaker backflow preventer. The Wilkins 460XL is similar to the Wilkins 720A and other Zurn vacuum breakers in that it uses a check valve to prevent polluted water from entering the potable water pipes through back siphonage. The Wilkins 460XL also has test cocks and shut-off valves. However, the Wilkins 460XL also has the added benefit that it is designed to reduce or prevent spillage from occurring.
The Wilkins 460XL is appropriate for high risk applications.
The Wilkins 460XL allows a maximum pressure of 150 psi (10.3 bar).
Wilkins BFP-9
The BFP-9 is a hose bib vacuum breaker backflow preventer that prevents a back siphon from entering the potable water pipes while a hose is being used.
The BFP-9 allows maximum working pressure of maximum pressure of 125 psi (8.6 bar).
Febco Backflow Preventers:
Febco LF510
The Febco LF510 is a lead free dual check backflow preventer.
The Febco LF510 allows a maximum pressure of 150 psi (10.3 bar).
Febco 715
The Febco 715 is a vacuum breaker backflow preventer.
The Febco 715 allows a maximum pressure of 150 psi (10.3 bar).
Febco 765
The Febco 765 is a Febco pressure vacuum breaker. The Febco 765 PVB includes two shut off valves so that the water is able to be turned off at the backflow. The Febco 765 is a Febco vacuum breaker that has two test cocks for draining and testing. The Febco 765 PVB uses a check valve called a poppet that can close to prevent back siphonage from reversing course and entering the potable water supply. The Febco 765 also has an air opening port.
The Febco 765 allows a maximum pressure of 150 psi (10.3 bar).
Febco 767
The Febco LF767FR is a lead free, freeze-resistant Febco vacuum breaker. The LF767FR is a Febco pressure vacuum breaker. The Febco 767 is a PVB or pressure vacuum breaker. The LF767FR includes two shut off valves so that the water is able to be turned off at the backflow. The Febco 767 also has test cocks for draining and testing.
The Febco 767 allows a maximum pressure of 150 psi (10.3 bar).
Febco 825Y
The Febco 825Y is a Febco RPZ with four test cocks and two shut-off valves. The Febco 825Y reduced pressure zone assembly is appropriate for high hazard applications.
The Febco 825Y allows maximum working pressure of 175 psi (12.06 bar).
Febco 825YA
The Febco 825YA is a small footprint ‘N’ shaped design Febco RPZ with four test cocks and two shut-off valves. The Febco 825 YA reduced pressure zone assembly is appropriate for high hazard applications.
The Febco 825YA allows maximum working pressure of 175 psi (12.06 bar).
Febco 850
The Febco 850 is a small in-line design double check valve assembly backflow preventers. The Febco 850 has shut-off valves that can be closed off so that the water is able to be turned off at the ball valves on the backflow itself. The Febco 850 has two independent, spring-loaded check valves, and four test cocks as well.
The Febco 850 allows maximum working pressure of 175 psi (12.06 bar).
Febco 860
The Febco 860 small reduced pressure zone backflow preventer RPZ has shut off valves so that the water is able to be turned off at the RPZ backflow. The Febco 860 backflow also has test cocks for draining and testing the Febco 860. The Febco 860 has two independent, spring-loaded check valves and a vent, as well. The Febco 860 is available with or without unions.
The Febco 860 is appropriate for high hazard health applications, and commercial, residential, and industrial settings.
The Febco 860 allows maximum working pressure of 175 psi (12.06 bar).
Febco LF860
The Febco LF860 small reduced pressure zone backflow preventer RPZ has shut off valves so that the water is able to be turned off at the RPZ backflow. The Febco LF860 backflow also has test cocks for draining and testing the Febco LF860. The Febco LF860 has two independent, spring-loaded check valves and a vent, as well. The Febco LF860 is available with or without unions.
The Febco LF860 is appropriate for high hazard health applications, and commercial, residential, and industrial settings.
The Febco LF860 allows maximum working pressure of 175 psi (12.06 bar).
Watts Backflow Preventers:
Watts 007
The Watts 007 double check valve assembly backflow preventer has shut-off valves that can be closed off so that the water is able to be turned off at the ball valves on the backflow itself. The Watts 007 has two independent, spring-loaded check valves, and four test cocks as well.
The Watts 007 is not appropriate for health hazard applications.
The Watts 007 allows maximum working pressure of 175 psi (12.06 bar).
Watts 8
The Watts 8 hose connection vacuum breaker backflow preventer helps prevent back siphonage from backing up into the potable water supply from hose use.
The Watts 8 allows maximum working pressure of maximum pressure of 125 psi (8.6 bar).
Watts 009
The Watts 009 reduced pressure zone assembly RPZ backflow preventer has shut off valves so that the water is able to be turned off at the RPZ backflow. The Watts backflow preventer 009 also has test cocks for draining and testing. The Watts 009 has two independent, spring-loaded check valves and a vent, as well.
The Watts 009 is appropriate for high hazard health applications, and commercial, residential, and industrial settings.
The Watts 009 allows maximum working pressure of 175 psi (12.06 bar).
The Watts 9D is a dual check valve backflow preventer with an intermediate atmospheric vent.
The Watts 9D backflow preventer has two redundant, spring loaded check valves to help prevent water from backing up and reversing course and mixing with the potable water pipes.
The Watts 9D is not appropriate for health hazard applications.
The Watts 9D allows minimum working pressure of 25psi (172kPa) and maximum working pressure of 175psi (12.1 bar).
Watts 188A
The Watts 188A is an anti-siphon vacuum breaker backflow preventer helps prevent back siphonage from backing up into the potable water supply.
The Watts 188A allows maximum working pressure of maximum pressure of 125 psi (8.6 bar).
Watts 719
The Watts 719 double check valve assembly backflow preventer has shut-off valves that can be closed off so that the water is able to be turned off at the ball valves on the backflow itself. The Watts 719 has two independent, spring-loaded check valves, and four test cocks as well.
The Watts 719 is not appropriate for health hazard applications.
The Watts 719 allows maximum working pressure of 175 psi (12.06 bar).
Watts 800M4QT
The Watts 800M4QT anti-siphon irrigation vacuum breaker backflow preventer is a PVB or pressure vacuum breaker. The Watts 800M4 includes two shut off valves so that the water is able to be turned off at the backflow. The Wilkins pressure vacuum breaker also has test cocks for draining and testing. The Watts 800M4QT uses a check valve that can close to prevent back siphonage from reversing course and entering the potable water supply.
The 800M4QT is appropriate for high hazard health applications, including commercial and residential irrigation settings.
The Watts 800M4QT allows a maximum pressure of 150 psi (10.3 bar) and a minimum pressure of 15psi (55kPa).
Watts 919
The Watts 919 reduced pressure zone assembly RPZ valve has shut off valves so that the water is able to be turned off at the RPZ backflow. The Watts 919 backflow also has test cocks for draining and testing the Watts 919. The Watts 919 has two independent, spring-loaded check valves and a vent, as well.
The Watts 919 is appropriate for high hazard health applications, and commercial, residential, and industrial settings.
The Watts 919 allows maximum working pressure of 175 psi (12.06 bar).
Watts LF7
The Watts LF7 lead free bronze dual check valve backflow preventer has two redundant, spring loaded check valves to help prevent back siphon from allowing water into the potable water pipes.
The Watts LF7 is not appropriate for health hazard applications.
The Watts LF7 allows minimum working pressure of 10psi (69 kPa) and a maximum working pressure of 150psi (10 bar).
Watts NF8
The Watts NF8 hose connection vacuum breaker backflow preventer helps prevent back siphonage from backing up into the potable water supply from wall and yard hydrants.
The Watts NF8 Hose Connection allows maximum working pressure of maximum pressure of 125 psi (8.6 bar).
Watts LFN9-CD
The Watts LFN9-CD field testable hose connection backflow preventer helps prevent back siphonage and low-head backpressure (10ft. or less) from backing up into the potable water supply from hose connection use.
The Watts LFN9-CD allows maximum working pressure of maximum pressure of 125 psi (8.6 bar).
The information in this article is primarily about irrigation system backflow preventers. So, if you do not see your backflow preventer here, again, you can reach out to your county, city, town, or other municipality to get additional information. Or you can contact a licensed backflow tester to ask them. If you still strike out, maybe try a master plumber.
Alright, that is the scoop on backflow preventers. Now when someone asks you,”what is a backflow device?” You can impress them with your vast knowledge on the subject. And let’s be realistic, when was the last time you went to a dinner party where you weren’t asked, “What is a backflow valve?” Never? Yeah, that’s what I figured.
Best of luck!
- Mr. Irrigation