Your pool filter's pressure gauge is one of the simplest diagnostic tools on the equipment pad. The important number is not a universal PSI—it is how today's reading compares with your system's normal clean operating pressure.
When pressure is higher than normal
A dirty filter is a common cause, but restrictions downstream of the pump, closed valves or other flow problems can also affect pressure. Follow the equipment manufacturer's procedures before assuming the cartridge alone is responsible.
When pressure is lower than normal
Low pressure can indicate insufficient water reaching the pump or another restriction on the suction side. A clogged skimmer basket, pump basket, low water level or air entering the system are examples worth checking.
Watch for sudden changes
A sudden pressure change deserves more attention than a slow, predictable rise as the filter loads with debris.
If you're replacing or upgrading equipment, browse Pumps & Filtration and Replacement Parts.