One small valve keeps your entire system pressurized between pump cycles. When it fails, the symptoms look like a dozen other problems — here's how to tell it's the valve.
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The check valve is a one-way valve that keeps water from flowing backward down the well after the pump shuts off. Without it, water in the pipe above the pump would drain back into the well every time the pump stops, and the pump would have to re-prime and push that column of water back up on every single cycle. Most systems have at least one check valve at the pump itself, and deeper wells often have additional in-line check valves every 100-200 feet of pipe.
Quick test: Shut off the pump breaker, open a faucet, and watch the pressure gauge at the tank. If pressure drops to zero almost instantly rather than bleeding down gradually as the tank empties, a check valve is likely stuck open or has failed.
On a submersible pump, the first check valve is usually built into or threaded directly onto the pump discharge, meaning a failed valve often requires pulling the pump — a job most homeowners hire out. Additional in-line check valves along the drop pipe are more accessible if you have record of their depth from the well installer.
Rapid pressure loss and short cycling can also mean your pressure tank has lost its air charge. Check the tank's air pre-charge first (with power off and tank drained) since that's a 5-minute fix, before assuming you need to pull the pump for a check valve.
A single check valve at the pump has to hold back the full weight of the entire water column in the drop pipe every time the pump stops — on a 300-foot well, that's a significant, constant static load on one valve. Adding in-line check valves every 100-200 feet breaks that column into shorter segments, so each valve only holds back its own section instead of the whole depth. This reduces wear on any single valve and means a failure is less catastrophic — you lose pressure from one segment rather than the entire column at once.
An in-line check valve along the drop pipe is comparatively simple to access if you know its depth, though it still typically requires a partial pump pull. The valve built into the pump discharge itself requires pulling the entire pump assembly, same as a pitless adapter or torque arrestor job. Parts cost is minor — usually $20-$60 for the valve itself — but labor for the pump pull typically runs $300-$800 depending on depth, since that's where nearly all the cost and time in this repair actually goes.
Check valves rely on a clean seat-to-seal contact to hold pressure — sand or sediment particles caught in that seat prevent it from sealing fully, which is one of the more common causes of check valves failing well before their typical 10-15 year lifespan. Wells with any history of sand or sediment in the water benefit from a sediment filter installed after the pressure tank, which protects not just the check valve but the pressure switch and fixtures downstream as well.
Only if it's an in-line valve along the drop pipe rather than the one built into the pump discharge. The pump-mounted valve requires pulling the whole assembly.
10-15 years typically, though sediment and sand in well water can cause premature wear on the valve seat.
A waterlogged tank causes gradual short cycling as the air cushion shrinks over months. A failed check valve causes sudden, dramatic pressure loss the moment the pump stops.
Prevents the backflow that causes priming failures and pressure loss.
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