Quick Answer:
If a shower drip gets worse when your house pressure is high, higher static pressure or short pressure spikes are likely pushing a small leak past the cartridge or valve seat. Measure your house pressure with a simple gauge at an outdoor hose bib or laundry connection to confirm. If pressure is above the normal 40–60 psi range or fluctuates, addressing the pressure or calling a plumber is the safest next step.
Why This Happens
Plumbing valves and cartridges rely on rubber seals and seats to stop water. When household water pressure is higher than normal, even a tiny imperfection or hard-worn seal can allow water to pass. Pressure spikes — brief bursts well above your normal pressure — can push water through a valve that otherwise seems fine.
- Higher static pressure increases the force on seals, making small leaks more noticeable.
- Thermal expansion (hot water heating) or pressure spikes from pumps or the main can make intermittent dripping worse.
- Older cartridges or mineral buildup can prevent a perfect seal even at normal pressure.
Step-by-Step What to Do
1. Measure the house water pressure
Use a simple pressure gauge that screws onto a hose bib or the laundry tub spigot. Take the reading with all fixtures off so you get the static pressure. Typical residential pressure is 40–60 psi. If you see readings above 80 psi or large swings, that confirms high pressure is a likely cause.
2. Watch when the drip changes
- Note whether the drip is constant, increases during use elsewhere, or after the water has been heated. This helps distinguish a worn valve from thermal expansion or intermittent pressure spikes.
- If the drip behaves differently after long hot showers, see the explanation about thermal effects — check Dripping only after long showers for that pattern.
3. Check the shut-off and cartridge
- Shut off the local shut-off valves (if present) and see if the drip stops. If it continues, the problem may be on the supply side or internal to the valve body.
- Inspect the cartridge for obvious damage or mineral buildup. Replacing the cartridge often fixes leaks, but if you replace it and the drip persists, check the seat and valve body.
- If you recently replaced the cartridge and now see a drip only under higher pressure, read guidance on Dripping after replacing cartridge for troubleshooting common installation or fit issues.
4. Consider a pressure-reducing valve (PRV) or service
If your measured pressure is consistently high, installing a PRV at the main supply reduces stress on all fixtures. A PRV also smooths spikes that make small leaks obvious. A licensed plumber should size and install a PRV for best results.
5. Test after each change
- After any repair or adjustment, re-measure pressure and observe the drip at different times of day and after hot-water use.
- Keep records: pressure readings, dates of repair, and how the drip responded. This helps a plumber if you need one.
What Not to Do
- Don’t ignore high pressure — pressure spikes can damage valves, fittings, and appliances over time. If pressure is high or unstable, a plumber is appropriate.
- Don’t overtighten parts trying to stop a drip; that can damage seats, cartridges, or threads and make the leak worse.
- Don’t assume the cartridge is the only issue; the valve body, seats, or supply side pressure can be the real cause.
When to Call a Professional
- If your gauge shows pressure consistently above about 80 psi or you see frequent pressure swings.
- If you are uncomfortable shutting off supplies, removing cartridges, or if the leak continues after you’ve replaced parts.
- If you need a pressure-reducing valve installed or your home has no main shut-off that you can safely operate.
Safety Notes
- Before working on the valve, shut off the water at the fixture shut-offs or the main and open a faucet to relieve pressure.
- Be careful with hot water — open a cold tap first to avoid scalding when relieving pressure.
- If you’re unsure about tools, plumbing parts, or isolating the water safely, stop and call a licensed plumber.
Common Homeowner Questions
- Will a drip waste a lot of water?
Yes — even a small steady drip can waste hundreds of gallons a month if left unaddressed. - What pressure is safe for my home?
Around 40–60 psi is normal; above 80 psi is high and worth addressing. - Can I replace the cartridge myself?
Often yes if you’re handy and can shut off the water, but call a plumber if you find unexpected corrosion, no local shut-offs, or persistent leaks after replacement.
For more related articles, see the Dripping Showerhead After Shutoff hub.