Quick Answer:
If a leak appears as soon as service is resumed, it’s usually a loose union, a failed gasket, or a valve issue that shows up under pressure. Shut the water off, inspect the meter and unions, then tighten the fittings evenly and replace any damaged gasket. If the leak continues or the meter or valve is damaged, call a professional or the utility.
Why This Happens
- When water is off for repairs or winter, rubber gaskets and O-rings can dry, shift, or crack. Once pressure returns, they can fail at the union or meter joint.
- Union nuts can relax or be disturbed during work, so they leak when the system is pressurized again.
- Corrosion or debris pushed into the joint during service can prevent a proper seal.
- Sometimes the issue is a valve part or handle that was stressed by the shut-off/turn-on process; if that’s the cause see meter valve leaking after city repair.
Step-by-Step What to Do
1. Stop the water and make the area safe
Locate and close your house shut-off or curb stop. If you cannot find it, contact the utility before trying anything else. Place a bucket under the meter and clear the area of trip hazards.
2. Do a quick visual check
- Look for water at joint faces, around union nuts, or dripping from the meter case.
- Note whether the leak is a steady stream, a drip, or only when pressure is applied.
3. Identify gasket or union failure
Open the union close to the meter and inspect the gasket or O-ring. A split, flattened, or missing gasket is a common cause. Also inspect the union nut faces and the male/female seating surfaces for corrosion or debris.
4. Tighten evenly
If the gasket and seating surfaces look intact, reassemble and tighten the union nuts evenly. Use two wrenches and alternate turns on each nut so the joint closes straight. Tighten only until snug—avoid excessive force.
5. Replace the gasket or O-ring if needed
- Drain residual water, separate the union, and remove the old gasket.
- Fit the correct-sized replacement gasket or O-ring made for water meters and unions, then reassemble and tighten evenly.
6. Restore water slowly and watch
Open the shut-off slowly to let pressure build gradually. Watch the repaired joint for several minutes, then recheck after an hour to ensure the seal holds.
What Not to Do
- Do not ignore seepage at meter.
- Do not overtighten fittings until metal parts deform—too much force can crack the meter or union faces.
- Do not substitute plumber’s tape on a gasketed union; tape does not replace a damaged O-ring or seat surface.
- Do not remove or tamper with utility-owned meter hardware without contacting the utility first.
When to Call a Professional
- If tightening and a gasket swap don’t stop the leak.
- If the meter body, union faces, or threads are visibly cracked or corroded.
- If a valve is broken or the handle won’t operate—especially if you see a bent or snapped control; in that case check guidance on meter valve handle broken.
- If you’re unsure about ownership of the meter or whether the utility must handle repairs.
Safety Notes
- Always shut off water and relieve pressure before disassembling a union.
- Wear gloves and eye protection; older systems may have sharp corrosion or mineral buildup.
- If a fitting is seized, avoid excessive force that could break the meter; call a plumber instead.
- Know local rules: some utilities require their crews to handle meter-side repairs—contact them if in doubt.
Common Homeowner Questions
- Why did the leak only start after service resumed? Because pressure exposes weak seals or loose fittings that weren’t leaking while the system was depressurized.
- Can I fix this with tape or sealant? No. Tape won’t seal a failed gasket at a union; the gasket or O-ring usually needs replacement.
- How long can I wait before calling a pro? Do not wait if it’s more than a slow drip; persistent leaks can cause damage and should be fixed promptly or inspected by a professional.