Description
Foot Valves
A foot valve is a type of one-way valve installed at the bottom end of a pump suction pipe. It is normally positioned inside a water source such as a tank, reservoir, dam or well.
The valve allows water to flow towards the pump but prevents the water from flowing backwards when the pump stops.
The valve is commonly fitted with a strainer or mesh screen. The strainer helps prevent dirt, leaves, stones and other debris from entering the suction pipe and reaching the pump.
In a typical pumping system:
Water source → Foot valve → Suction pipe → Pump → Delivery pipe
The foot valve therefore performs two important functions: maintaining water in the suction line and helping protect the pump from debris.
How Does a Foot Valves Work?
When the pump starts, suction is created inside the pipe. This suction opens the valve, allowing water to enter the suction line.
When the pump is switched off, the water naturally tries to flow back into the source. The valve closes and prevents this reverse movement.
Keeping water inside the suction pipe is important because many surface pumps need to remain primed to operate correctly.
Without an effective foot valve, the water may drain back into the tank, dam or well. The next time the pump starts, it may need to be primed again.
Foot Valves Sizes and Their Uses
Foot valves are available in different sizes. The correct size should normally match the suction pipe and be appropriate for the pump’s required flow rate.
Common sizes include 1 inch, 1¼ inch, 1½ inch, 2-inch, 2½ inch, 3 inch and 4 inch.
| Foot Valve Size | Common Use | Typical Application |
| 1 inch | Small water systems | Small tanks, gardens and domestic pumps |
| 1¼ inch | Small to medium pumps | Small farms and irrigation systems |
| 1½ inch | Medium-flow pumping | Vegetable farms and water transfer |
| 2 inches | Higher water flow | Irrigation, tanks and medium farms |
| 2½ inch | Large pumping systems | Commercial farms and water transfer |
| 3 inches | High-flow applications | Large irrigation systems and reservoirs |
| 4 inches | Very high flow | Large farms and commercial water systems |
Foot Valve vs Non-Return Foot Valve
A standard foot valve is essentially a one-way valve installed at the bottom of a suction pipe, usually with a strainer. Its main purpose is to allow water into the suction pipe while preventing it from flowing backwards.
A non-return foot valve combines the same one-way or non-return function with the foot-valve arrangement. It emphasises that the valve prevents reverse flow.
Standard Non-Return Valve
A normal non-return valve is designed primarily to prevent water from flowing backwards. It may be installed along a pipeline, depending on the system design.
It does not necessarily have a strainer and is not necessarily designed to sit at the bottom of a suction pipe.
Foot Valve
A foot valve is specifically designed for installation at the end of a suction pipe. It commonly includes a strainer to keep debris away from the pump.
Simple Difference
| Feature | Foot Valve | Non-Return Valve |
| Main purpose | Prevents backflow and maintains suction-line water | Prevents reverse flow |
| Installation | Usually at bottom of suction pipe | Can be installed at different points |
| Strainer | Commonly included | Not always included |
| Suitable for pump suction | Yes | Depends on design |
| Helps maintain pump prime | Yes | Not necessarily |
| Debris protection | Usually provided by strainer | Usually not provided |
A non-return foot valve combines the one-way operation with the foot-valve installation arrangement.
Foot Valves Uses
Foot valves are useful in many water systems.
Irrigation
Farmers use foot valves when pumping water from dams, rivers, tanks and reservoirs to irrigation systems.
They are suitable for systems supplying:
- Drip irrigation
- Sprinklers
- Greenhouses
- Vegetable farms
- Orchards
Water Tanks
A foot valve can be installed at the suction end when transferring water from one tank or reservoir to another.
Surface Pumps
Foot valves are particularly useful with surface pumps that draw water through a suction pipe.
Borehole-Related Systems
The suitability of a foot valve in a borehole depends on the pump type and system design. It should not be installed blindly in every borehole system because submersible pumps have different operating principles.
Benefits of Using a Foot Valve
A quality foot valve offers several benefits.
Maintains pump prime: It helps keep water in the suction pipe after the pump stops.
Reduces repeated priming: The pump can restart without losing all the water from the suction line.
Protects the pump: The attached strainer helps prevent large particles from entering the pump.
Improves pumping reliability: A properly sized valve supports consistent water flow.
Reduces water wastage: It prevents water in the suction line from draining back unnecessarily.
Factors to Consider when Choosing the Right Foot Valves
- Suction Pipe Size- Match the valve connection to the suction pipe size unless the system has a properly designed reducer or adapter.
- Pump Capacity- Check the pump’s recommended suction pipe size and flow rate.
- Water Source- Consider whether you are drawing water from a tank, dam, river, reservoir or a well. Dirty water may require a stronger strainer or additional filtration.
- Material- Foot valves are commonly available in materials such as brass, cast iron, stainless steel and durable engineering plastics. Choose a material suitable for your water conditions and expected service.
- Strainer Quality- A strong, properly sized strainer is important because it prevents debris from entering the suction line.
Foot Valve Installation Tips
For good performance, install the foot valve correctly.
Place it at the lower end of the suction pipe and keep it sufficiently submerged to prevent the pump from drawing air.
Do not place it directly on muddy ground where the strainer can become blocked. Where possible, keep it above the bottom of the water source while ensuring it remains underwater during pumping.
Before starting the pump, ensure the suction pipe and pump are correctly primed according to the pump manufacturer’s instructions.
Check the valve regularly for:
- Blocked strainers
- Cracks
- Leakage
- Corrosion
- Worn seals
- Loose connections
