Shutoff Valve Problems
Please note: much of the information below references irrigation backflow assemblies, which is the vast majority of the assemblies we test. Much of this information is also applicable to backflow equipment serving other uses (such as fire or domestic water) downstream.
Properly-working shutoff valves (on your backflow assembly, and often upstream), are vital - we open and close these up to ten times during our test procedure. We use them to pressurize and bleed our gauge, isolate check valves for a test, restore water service after testing (if on when we arrive), prevent water from going downstream (if off when we arrive), and more. They're also an important part of other repair and maintenance tasks downstream, such as: winterization, spring start-up of irrigation equipment (if that's what's served by your backflow assembly), repairs, and shutting water off in the event of leaks or damage (note: we do not offer these services).
We sometimes encounter problems with shutoff valves that either prevent us operating them, or make it very risky to do so. When these become concerning, we will ask for customers to have repairs made as a condition of future testing. Usually the issues we see are related to corrosion of the valve handles and are years in the making. The probability of these problems increase with age of the assembly, stiffness of the shutoff valves, and progressive corrosion of the handles. Handles that are missing or in poor condition can keep us from operating a valve, knowing its position, or even from restoring water service after testing.
We have created this page to provide a visual guide to shutoff valves, the issues we encounter with them, and ways that customers can help ensure that they last as long as possible. Replacing these can be costly! A backflow assembly replacement alone usually costs around $1,000 (give or take a few hundred), but there are some common-sense precautions that can extend its useful life.
Handle Corrosion
Corrosion! It's the #1 reason that backflow assemblies need to be replaced, and shutoff valve handles are usually the parts on the assembly most susceptible to it. The progression in the photo below shows what happens when shutoff handles corrode away:
1. New handle (or stainless handle)
2. Light surface rust
3. Rust starting to penetrate further into the metal
4. Advanced corrosion. The metal thin and weakens, eventually bending when the handle is operated. (This is when we'd begin to recommend repairs.)
5/6. The ends of the handles fall off, creating rusty, ragged edges that are dangerous to handle.
7. After the ends are gone, we're sometimes left with a boxy remnant. We may be able to operate with an adjustable wrench, if we're lucky.
8. Eventually, we're left with a mass of corroded, rounded metal. In this condition, it is nearly impossible to tell what position the valve is in before leaving the jobsite. If we're lucky, we can turn the remnant with vise grips, but this can be risky: the material can round out even more and potentially prevent us from operating the valve. If this happens when the valve is closed, it may not be possible to restore service downstream until the valve is replaced.
9. The remnant eventually corrodes away, leaving a bare valve stem. The stem may already be damaged due to the use of vise grips during earlier stages of corrosion. At this stage, the valve may be operable using an adjustable wrench. (See Replacement Handles, below, for details on why we do not replace shutoff handles.)
10. As a valve is operated without its original handle, the stem will round off until an adjustable wrench can no longer grip the stem, making the valve very risky to operate. The material has attenuated and weakened, with no safe way to grip what's left, and there's a high probability that the valve will become inoperable during your backflow test, either because we cannot grip it, or because the remaining metal is left finally gives out (shears off).
11. Example of a sheared valve stem. This can be due to long-term weakening of the stem material (see #10) or poorly-fitting replacement handles, but we've also seen this on brand new assemblies that look fine visually, but which have preexisting weaknesses in the material that are undetectable to the naked eye and only become apparent when the valve (literally) falls off in our hands while being operated! The stem will detach somewhere along its length, and the nut will fall off with part of the stem still lodged in the threads. This latter scenario is rare, but we have documented a couple dozen cases of detached valve stems over the last decade or so, many of which we find already separated, with the nut and no-longer-attached stem lying together in the box.
Handles with conditions in the 4-10 range can prevent us from operating the shutoff valves, determining valve positions, completing a test, or even restoring valves to their original positions - in worst-case scenarios, this can lead to emergency repairs being required before water can be used downstream. We try to avoid these scenarios whenever possible, by declining testing on assemblies that pose a high risk due to shutoff handle condition.
Replacement Handles
The photo below shows two views of the same shutoff valve: one with the handle and nut attached, and one with the handle removed. With the handle removed, you can see the valve stem, which is the part of the valve that rotates when the handle is turned. Inside the valve, an interior component turns to block off water, or allow it to flow through. When new, this stem is rounded and threaded on two sides, and flat and smooth on two others. Handles are precision-machined to exactly fit the valve stem, and a threaded nut follows to fasten it closely to the body. We used to install stainless replacement handles when the threads on the stem were in good condition. However, we have found that new stainless handles from the manufacturer are often slightly too large for the stem, with some "play" from side to side before the handle actually grips the valve stem. Over time, the poor fit will cause the handle to score a groove in the valve stem which weakens the material, drastically increasing the chances that the valve stem will snap off and leave no further way to operate the shutoff valve. If this happens when the valve is in the closed position, the shutoff valve will need to be replaced before water service can be restored downstream. This has happened to us a few times while testing, and it is the reason we always advise against replacing just the shutoff handle. A replacement handle may seem like a cheap, easy, and quick fix, but it can create a future need for emergency plumbing repairs. When handles go bad, the two best options are to replace the entire shutoff valve or the entire backflow assembly, depending on the overall condition. Please do not install aftermarket shutoff valves in place of those originally installed on your backflow assembly, as this will void the USC approval for your assembly. Most manufacturers sell exact replacements for the original shutoff valves.
Properly-working shutoff valves (on your backflow assembly, and often upstream), are vital - we open and close these up to ten times during our test procedure. We use them to pressurize and bleed our gauge, isolate check valves for a test, restore water service after testing (if on when we arrive), prevent water from going downstream (if off when we arrive), and more. They're also an important part of other repair and maintenance tasks downstream, such as: winterization, spring start-up of irrigation equipment (if that's what's served by your backflow assembly), repairs, and shutting water off in the event of leaks or damage (note: we do not offer these services).
We sometimes encounter problems with shutoff valves that either prevent us operating them, or make it very risky to do so. When these become concerning, we will ask for customers to have repairs made as a condition of future testing. Usually the issues we see are related to corrosion of the valve handles and are years in the making. The probability of these problems increase with age of the assembly, stiffness of the shutoff valves, and progressive corrosion of the handles. Handles that are missing or in poor condition can keep us from operating a valve, knowing its position, or even from restoring water service after testing.
We have created this page to provide a visual guide to shutoff valves, the issues we encounter with them, and ways that customers can help ensure that they last as long as possible. Replacing these can be costly! A backflow assembly replacement alone usually costs around $1,000 (give or take a few hundred), but there are some common-sense precautions that can extend its useful life.
Handle Corrosion
Corrosion! It's the #1 reason that backflow assemblies need to be replaced, and shutoff valve handles are usually the parts on the assembly most susceptible to it. The progression in the photo below shows what happens when shutoff handles corrode away:
1. New handle (or stainless handle)
2. Light surface rust
3. Rust starting to penetrate further into the metal
4. Advanced corrosion. The metal thin and weakens, eventually bending when the handle is operated. (This is when we'd begin to recommend repairs.)
5/6. The ends of the handles fall off, creating rusty, ragged edges that are dangerous to handle.
7. After the ends are gone, we're sometimes left with a boxy remnant. We may be able to operate with an adjustable wrench, if we're lucky.
8. Eventually, we're left with a mass of corroded, rounded metal. In this condition, it is nearly impossible to tell what position the valve is in before leaving the jobsite. If we're lucky, we can turn the remnant with vise grips, but this can be risky: the material can round out even more and potentially prevent us from operating the valve. If this happens when the valve is closed, it may not be possible to restore service downstream until the valve is replaced.
9. The remnant eventually corrodes away, leaving a bare valve stem. The stem may already be damaged due to the use of vise grips during earlier stages of corrosion. At this stage, the valve may be operable using an adjustable wrench. (See Replacement Handles, below, for details on why we do not replace shutoff handles.)
10. As a valve is operated without its original handle, the stem will round off until an adjustable wrench can no longer grip the stem, making the valve very risky to operate. The material has attenuated and weakened, with no safe way to grip what's left, and there's a high probability that the valve will become inoperable during your backflow test, either because we cannot grip it, or because the remaining metal is left finally gives out (shears off).
11. Example of a sheared valve stem. This can be due to long-term weakening of the stem material (see #10) or poorly-fitting replacement handles, but we've also seen this on brand new assemblies that look fine visually, but which have preexisting weaknesses in the material that are undetectable to the naked eye and only become apparent when the valve (literally) falls off in our hands while being operated! The stem will detach somewhere along its length, and the nut will fall off with part of the stem still lodged in the threads. This latter scenario is rare, but we have documented a couple dozen cases of detached valve stems over the last decade or so, many of which we find already separated, with the nut and no-longer-attached stem lying together in the box.
Handles with conditions in the 4-10 range can prevent us from operating the shutoff valves, determining valve positions, completing a test, or even restoring valves to their original positions - in worst-case scenarios, this can lead to emergency repairs being required before water can be used downstream. We try to avoid these scenarios whenever possible, by declining testing on assemblies that pose a high risk due to shutoff handle condition.
Replacement Handles
The photo below shows two views of the same shutoff valve: one with the handle and nut attached, and one with the handle removed. With the handle removed, you can see the valve stem, which is the part of the valve that rotates when the handle is turned. Inside the valve, an interior component turns to block off water, or allow it to flow through. When new, this stem is rounded and threaded on two sides, and flat and smooth on two others. Handles are precision-machined to exactly fit the valve stem, and a threaded nut follows to fasten it closely to the body. We used to install stainless replacement handles when the threads on the stem were in good condition. However, we have found that new stainless handles from the manufacturer are often slightly too large for the stem, with some "play" from side to side before the handle actually grips the valve stem. Over time, the poor fit will cause the handle to score a groove in the valve stem which weakens the material, drastically increasing the chances that the valve stem will snap off and leave no further way to operate the shutoff valve. If this happens when the valve is in the closed position, the shutoff valve will need to be replaced before water service can be restored downstream. This has happened to us a few times while testing, and it is the reason we always advise against replacing just the shutoff handle. A replacement handle may seem like a cheap, easy, and quick fix, but it can create a future need for emergency plumbing repairs. When handles go bad, the two best options are to replace the entire shutoff valve or the entire backflow assembly, depending on the overall condition. Please do not install aftermarket shutoff valves in place of those originally installed on your backflow assembly, as this will void the USC approval for your assembly. Most manufacturers sell exact replacements for the original shutoff valves.