Many users encounter this situation after installing a water pump:

“The pump worked fine the first time, but after stopping it, it won’t draw water again.”
“I have to prime the pump manually every time—what’s going on?”

These problems are almost always related to the installation setup and the absence of a foot valve.
When a pump is installed above the water level (a “low-water-level” or suction-type installation), a foot valve is absolutely essential for proper operation.

1. What Is a “Low-Water-Level Installation”?

A low-water-level installation, also known as a suction lift installation, means:

The water pump is installed above the water surface, and it draws water upward through a suction pipe.

This configuration is common in:

• Wells, ponds, or reservoirs
• Farmland irrigation systems
• Industrial cooling or circulation setups

Because the pump is positioned higher than the water source, it must rely on suction to draw water up through the pipe.
That’s why a foot valve is so critical in this setup.

2. What Does a Foot Valve Do?

A foot valve (also called a check valve or non-return valve) is installed at the very bottom of the suction pipe, usually combined with a strainer.
Though small and inexpensive, it plays a vital role in keeping your pump system working reliably.

The foot valve serves three key purposes:

1. Prevents Backflow
   When the pump stops, the foot valve automatically closes to stop water in the suction line from flowing back into the source.
2. Maintains a Water Column in the Suction Line
   This keeps the suction pipe and pump casing full of water, preventing air from entering the system and ensuring the pump can start immediately next time.
3. Prevents Air Lock and Dry Running
   Without a foot valve, the suction line empties after each stop, causing air pockets that prevent priming and may lead to dry running or seal damage.

3. What Happens If You Don’t Install a Foot Valve?

If your suction-type installation lacks a foot valve, you’ll likely face these problems:

• The suction pipe empties after each shutdown
• You must manually prime the pump before every start
• The pump fails to draw water or takes a long time to do so
• The pump may run dry, leading to overheating or mechanical seal failure

For this reason, all manufacturers clearly specify:

“A foot valve must be installed for pumps located above the water level.”

4. Installation and Maintenance Tips

To ensure reliable operation:

1. Install the foot valve at the lowest point of the suction line, but keep it slightly above the bottom to avoid drawing in debris.
2. Use a strainer or filter screen to prevent solid particles from clogging the valve.
3. Ensure all joints and fittings are airtight—even a small air leak can ruin suction performance.
4. Check and clean the valve periodically to maintain smooth operation.

5. Conclusion

The foot valve may be small, but it’s one of the most critical components in a suction-type pump system.
For pumps installed above the water level, a properly functioning foot valve prevents water backflow, keeps the suction line primed, and ensures quick, reliable startup every time.

With a simple, inexpensive addition, you can extend the pump’s lifespan, save energy, and eliminate unnecessary maintenance.