Foot Valves and Suction Service

Q: Does Apex sell foot valves?

Not as a stocked line today. Apex carries the components — Y-strainers and check valves across several mechanisms — and can source a foot valve assembly or engineer an equivalent solution for a specific application.

Q: Can I use a foot valve on a vertical-down suction line?

Confirm the internal check mechanism first. A foot valve built around a gravity swing check inherits the same orientation limits as any swing check, while one built around a spring-loaded element does not.

Written by the Apex Flow Solutions technical desk — twenty years of industrial distribution experience behind every guide.

A foot valve lives at the bottom of a suction line, submerged in the source, and does two jobs at once: it strains debris out of the water before it reaches the pump, and it holds the line primed when the pump shuts off. Lose either function and you get a real, expensive problem — a pump that has to be re-primed by hand every time it cycles, or worse, one that pulls debris into its impeller and wears out early. This guide covers how foot valves work, why prime-holding matters, how the strainer and check functions integrate, and when a foot valve is the right call versus a plain inline check somewhere else in the system.

What a Foot Valve Actually Is

Strip away the name and a foot valve is a check valve — usually swing or spring-loaded internally — built into a strainer body and installed at the submerged inlet end of a suction line. It's not a separate mechanism so much as a specialized installation of check valve function: the check element keeps water from draining back down the suction line when the pump stops, and the strainer screen (built into the same body) keeps debris out of the pump on the way in. Because both jobs happen at the one point in the system where the pipe first meets an open source — a wet well, a tank, a river or pond intake — combining them into a single submerged unit is more practical than trying to install a separate check valve and strainer down in the water.

Why Prime-Holding Matters

A centrifugal pump has to be full of liquid to move liquid — that's what "priming" means, and it's also the pump's most vulnerable moment. Run a centrifugal pump dry, even briefly, and you risk overheating the seals and bearings, sometimes badly enough to need a rebuild. Without a foot valve, the water in a suction line drains back to the source every time the pump stops, which means every restart requires re-priming before the pump can safely run. On an intermittent-duty pump — irrigation, dewatering, a seasonal lift station — that's a re-priming cycle every single time it starts, which is exactly the kind of repeated manual step that eventually gets skipped under time pressure, with a dry-run failure right behind it.

A foot valve's check element holds the column of water in the suction line in place when the pump stops, so the line — and the pump — stays primed and ready for the next start without manual intervention.

Strainer Integration: Why It's Built In, Not Bolted On

The screen around a foot valve's inlet keeps sediment, leaves, and debris from the source out of the pump. This matters more at a submerged intake than almost anywhere else in a fluid system, because the intake sits directly in an open, often uncontrolled body of water — a pond, a tank with sediment on the bottom, a wet well that collects whatever washes in. Without screening at that point, a pump ingests whatever's in the water, which shortens impeller life and can jam a check valve's disc or poppet open on debris, defeating the prime-holding function at the same time it damages the pump.

Screen mesh selection follows the same logic as any strainer: coarser mesh protects the pump from serious debris with less flow restriction and less frequent cleaning; finer mesh protects tighter-clearance pumps but loads up and needs service more often. See our strainer mesh & sizing reference for how to think through that tradeoff — the same principles apply whether the screen is a standalone Y-strainer or built into a foot valve.

Foot Valve vs. Inline Check: When Each One Is the Right Call

These aren't competing options for the same job — they solve different placement problems:

Use a foot valve when the check has to live at the submerged inlet of a suction line pulling from an open source (tank, pond, wet well, river) and the pump needs to stay primed between cycles. This is a purpose-built installation, not a general-purpose substitute for a check valve anywhere else in the piping.
Use an inline, spring, swing, or ball check everywhere else in the system — pump discharge, mid-line backflow protection, chemical feed, metering — where the valve doesn't need to be submerged and doesn't need an integral strainer. Putting a plain check valve at a suction inlet without a strainer risks debris damage to the pump that a foot valve's screen would have caught.

If your suction source is a closed, clean tank with no debris risk and the line stays flooded (positive suction head, no drain-back path), a plain check valve without the strainer function may be adequate — but confirm that assumption before skipping the screen, since "clean tank" often turns out to have more sediment at the bottom than expected once it's been in service a year.

Clean, Repair, or Replace?

Pump won't stay primed between cycles → the check element itself has likely failed or is being held open by debris. Pull it, inspect the disc or poppet, and clean before assuming you need a new unit.
Screen is fouled with sediment or debris but the check element still holds prime → clean the screen. This alone often restores flow without touching the check function.
Screen is torn, corroded through, or the check element won't reseat after cleaning → replace. A damaged screen stops protecting the pump even if it looks mostly intact, and a check element that won't reseat has lost its prime-holding function for good.

An Honest Note on What We Stock

Apex doesn't currently carry dedicated foot valve assemblies as a stocked line. What we do carry are the components a foot valve combines — Y-strainers in brass and flanged ductile iron, and check valves across swing, spring/barrel, and ball-check mechanisms — so if your application calls for a foot valve specifically, tell us the pipe size, the source (tank, pond, wet well), and the debris load, and we'll source the correct assembly rather than sell you parts that don't actually solve a submerged-suction application. In some cases a strainer plus a separately mounted check valve just above the waterline is a workable substitute; in others, a true integrated foot valve is worth sourcing specifically for the reliability of a single submerged unit. We'll tell you honestly which one your job needs.

When Replacement Is the Better Option

The pump keeps losing prime even after the screen has been cleaned — that points to the check element itself, not debris, and a check element that won't reliably reseat is a replacement, not a cleaning job.
The screen is torn, corroded, or deformed rather than just dirty — a damaged screen lets debris through even when it still looks like it's doing its job.
The mesh size no longer matches the pump's clearance needs — if the pump or process has changed since the original foot valve was sized, the mesh may need to change with it rather than being cleaned and reinstalled as-is.
The combined headloss is pulling suction pressure toward cavitation on a pump with limited NPSH margin — that's a sizing problem the existing unit can't clean its way out of.

Sizing and Headloss Notes

A foot valve combines two flow restrictions — the strainer screen and the check element — in one body, so its headloss tends to run higher than either component alone. Undersizing a foot valve for the pump's actual suction flow compounds that restriction and can pull suction-side pressure down toward cavitation, especially on a pump with limited net positive suction head (NPSH) margin to begin with. Size to the pump's rated flow, not just the suction pipe's nominal diameter — the same principle covered in more depth in our check valve sizing guide.

Frequently Asked Questions

What does a foot valve do that a regular check valve doesn't?

A foot valve combines a check element with a built-in strainer screen in a single unit designed for submerged installation at the inlet of a suction line. A regular check valve alone doesn't screen debris, and installing one without a strainer at a submerged, open-source intake risks pump damage from ingested debris.

Why does my pump lose prime without a foot valve?

Without a check element holding the suction line's water column in place, the line drains back to the source every time the pump stops, leaving air in the line and requiring re-priming before the next safe start.

Does Apex sell foot valves?

Not as a stocked line today. We carry the components — Y-strainers and check valves across several mechanisms — and can source a foot valve assembly or engineer an equivalent solution for your specific application. Send us the pipe size and source conditions and we'll confirm the right approach.

Can I use a foot valve on a vertical-down suction line?

Confirm the internal check mechanism before assuming so — a foot valve built around a gravity swing check inherits the same orientation limits as any swing check, while one built around a spring-loaded element does not. Ask us for the specific mechanism if orientation is a concern.

Related products

Published performance data is general engineering reference, not a certification for your application. Confirm specifics against the manufacturer datasheet or ask us.

Need a foot valve sourced, or not sure if your application needs one?

Send us: pipe size · media · pressure · orientation · source (tank, pond, wet well) and debris load · a photo of the installation. We'll recommend the correct valve — or tell you if you don't need one. Request a quote and you'll have an answer from a person the same business day.