Leak after pressure change

Quick Answer:

If an outdoor spigot started leaking right after the city adjusted pressure or your pressure reducing valve (PRV) was changed, first measure the water pressure with a gauge, check the PRV and main shutoff for visible leaks or loose packing, and try gently tightening any accessible compression fittings. If pressure swings continue, the PRV may need recalibration or replacement — this is often best handled by a plumber.

Why This Happens

When municipal supply pressure changes or a PRV is adjusted, the change in force through the pipes can expose small weaknesses. A previously snug compression fitting can start weeping, seal material around the PRV can fail, or a packing nut on the main shutoff can loosen. Sudden or repeated pressure swings stress joints and old fixtures, so leaks can show up immediately after the change.

Step-by-Step What to Do

1. Measure the pressure before and after

Buy or borrow a simple water pressure gauge that screws onto an outdoor spigot or hose bib.
Record the static pressure reading before any work — then check it again after the municipal change or after the PRV was adjusted. Note whether pressure spikes above 60–80 psi or drops suddenly.
Measure at the same spigot both times for a consistent comparison.

2. Inspect the PRV and main shutoff for visible leaks or loose packing

Look near the PRV body and the main shutoff for drips, wetness, or mineral deposits that indicate a leak.
Check the packing nut (the small nut behind the valve handle) on the main shutoff for moisture. A loose packing nut will show slow seepage.
Watch the area while someone cycles a faucet — some leaks only show under flow or pressure changes.

3. Tighten accessible compression fittings, then retest

Use an adjustable wrench to give compression fittings a small quarter-turn if you see weeping. Tighten gently; over-tightening can damage fittings.
After tightening, re-measure pressure with the gauge and watch the repaired area for several minutes to confirm the leak stopped.

4. Recalibrate or replace the PRV if pressure swings persist

If your measured pressure keeps fluctuating or remains too high, the PRV may need adjustment or replacement.
Some PRVs have an adjustment screw for fine-tuning; follow the manufacturer’s instructions. If you’re unsure or the valve is old, replacement is the safer long-term fix.
Because PRV work can require special tools or gas/water codes, consider professional help for recalibration or replacement.

What Not to Do

Don’t assume tightening random fittings will fix post-change leaks — temporary fixes can hide a bigger problem.
Avoid makeshift patches or stuffing material into a PRV or valve to stop a leak. Do not attempt temporary fixes on PRVs that mask the issue.
Don’t ignore a new leak that started right after a municipal pressure change; if you can’t stabilize the pressure or the leak continues, call a pro.

When to Call a Professional

If the PRV shows an active leak or you see continuous high pressure after checking with a gauge.
If pressure swings correlate exactly with municipal activity and tightening fittings didn’t help.
If you’re uncomfortable working near the main shutoff or the PRV, or if replacement is needed.

For related situations, read about Spigot leaks after city outage and Leak worsens when water pressure high.

Safety Notes

Turn off the main shutoff before doing any significant repairs, and open a faucet to relieve pressure.
Wear eye protection and gloves when working on valves or fittings.
Do not disassemble a PRV unless you understand how to reinstall it and test pressure properly. Incorrect reassembly can create unsafe pressure conditions.

Common Homeowner Questions

How high is too high for home water pressure? — Sustained pressure above about 80 psi is generally too high and can cause leaks or damage.
Can I adjust the PRV myself? — Minor adjustments may be possible, but recalibration or replacement is often best done by a plumber if you’re unsure.
Will tightening a fitting always stop the leak? — No. Tightening can stop some compression fitting weeps, but if pressure changes caused damage inside a valve or the PRV, the leak may return.