Problem Summary
Filter pressure reads lower than the normal operating range for the system.
Unusually low filter pressure means less water than expected is reaching the filter, which is a flow problem rather than a filtration problem.
Possible Causes
Pump is starved of water (suction-side restriction)
A clogged skimmer basket, pump strainer basket, or partially closed suction valve reduces how much water actually reaches the pump and filter.
Pump losing prime or drawing in air
Air in the system reduces effective flow and shows up as low filter pressure alongside visible air bubbles at return jets.
Diagnostic Steps
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Check the skimmer basket and pump strainer basket for debris.
A clogged basket restricting suction flow is the most common cause and the first thing to rule out.
Solutions
Clear all suction-side baskets and check suction valves are fully open
Addresses cause: Suction-side restriction
This resolves the majority of low-pressure cases; re-check pressure after clearing.
When to Contact a Specialist
If pressure stays low after clearing baskets and opening valves fully, and the pump shows signs of air intake, see our related guide on a pump losing prime, or have the suction plumbing inspected for a leak.