Symptoms
- Pressure dropped noticeably after filter installation or over time since the last change
- Pressure is fine if the filter is bypassed
- Filter housing may look discolored or have visible sediment
- Flow restriction affects the entire house evenly
Likely causes
- CommonClogged filter cartridge from accumulated sedimentFilters are designed to trap particles, and once saturated, they significantly restrict flow until replaced.
- CommonWrong filter micron rating for your water's sediment levelA very fine filter can clog quickly if your water carries more sediment than the filter is rated to handle efficiently.
- PossibleFilter housing installed with a kink or restriction in the plumbingImproper installation, such as an undersized bypass or tight bend, can itself restrict flow independent of the filter.
- Less commonFilter overdue for replacement well past its rated capacitySome filters are rated for a certain volume or time period and lose effectiveness (and increase restriction) well past that point.
What to do
- Check the filter housing for a bypass valve, and if present, switch to bypass briefly to confirm the filter is indeed the cause of low pressure.
- If pressure returns to normal in bypass mode, this confirms the filter is restricting flow.
- Shut off water to the filter housing, usually via dedicated valves on each side.
- Open the housing (often by unscrewing counterclockwise, sometimes with a wrench) and remove the old cartridge.
- Inspect the cartridge for discoloration and buildup, and replace with a new one matching the same specifications.
- Check the O-ring on the housing for wear and lubricate lightly with silicone grease before reassembling.
- Turn water back on slowly, check for leaks at the housing, and confirm pressure has returned to normal.
Tools and parts
- Filter housing wrench
- Bucket (for water spillage)
Whole house filter replacement cartridgeSearch: “whole house water filter replacement cartridge”
When to call a pro
Call a plumber if pressure remains low even in bypass mode, since the issue may be elsewhere in the system, or if the housing itself needs replacement.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.