Hidden water running right now: what to do first
Hidden leaks do their damage slowly, until they do not.
- Close the main shutoff, normally where the water line enters the house near the meter.
- Turn off the water heater if you can see it is part of the leak, to protect the elements.
- Move electronics and boxes away from wet walls and floors.
- Call the 24/7 line. We schedule same-day and after-hours leak location for active water.
Test the meter before you call
Close every tap and appliance. Find the water meter, usually near where the line enters the house, and look for the small dial or triangle that spins when water is moving. If it spins with everything off, water is leaking somewhere between the meter and the fixtures.
If the meter is still, the leak may be a dripping fixture or the problem may be on the hot side. Home meter tests do not replace a plumber, but they save everyone time and tell us whether the leak is inside or on the line outside.
Where leaks hide and how we look
Different spots need different methods. The method list below is how we match tool to location.
High water bill
A bill that jumps with no change in habits points to a running toilet, an irrigation line or a buried leak. A toilet flapper test and a meter test narrow it fast.
Slab and floor
Warm spots, a hum or rising bills can mean a leak under concrete. Acoustic listening and thermal imaging trace it without breaking the slab first.
Walls and ceilings
Staining, bubbling paint or a musty smell guide us to the wall cavity. Moisture readings and pressure tests tell us which line is affected.
Crawlspace and exterior walls
Frozen supply lines in unheated spaces are a Minnesota winter pattern. We check for splits and tell you whether heat tape or reroutes make sense.
Buried water line
A wet patch in the yard or a drop in pressure can mean a break between the meter and the house. See water service line repair.
Irrigation
Zones that stay wet, or a meter that moves with the system off, point to a leaking head or buried line.
Common signs and what they usually mean
Use this as a rough guide, then call for a confirmed answer.
| Sign | Likely location | First step |
|---|---|---|
| Meter spins with everything off | Between meter and fixtures | Close the main and call |
| Warm floor spot | Hot line under the slab or floor | Turn off the water heater and call |
| Wet ceiling | Supply or drain line above | Shut the main, photograph, call |
| Hissing in the wall | Pressurized line | Shut the main and call |
| Sudden pressure drop | Service line or main valve | Check the meter and call |
Not every wet spot is a plumbing leak. Roof and window leaks look similar.
Water that crosses the line from city to you
The City of South St. Paul runs its own water utility from municipal wells. The service line from the building to the main belongs to the property owner, so a leak between the main and your house is your repair and a leak in the street main is the city's.
The city's lead inventory lists hundreds of lead and galvanized service lines still in the system, and the program offers replacements. If your leak is on an older service line, a replacement may be smarter than a repair, so ask the city about the program before we dig.
What affects the cost of leak detection
Locating a leak is priced by time and method, then repair is quoted separately.
Insurance often covers the water damage from a sudden leak but not the pipe itself or long-term seepage. Ask your carrier before you tear out drywall.
Sources for this page
Service line ownership and the lead inventory numbers come from the City of South St. Paul's utility pages. Buried piping depth comes from Minnesota Rules chapter 4714, and locate notice comes from Gopher State One Call. Repairs follow the Uniform Plumbing Code (UPC) as adopted in Minnesota. Methods listed follow common industry practice.
Questions people ask
Yes. The 24/7 line is open on nights and weekends. For active leaks we book same-day appointments when available and shut-off guidance over the phone.
Do a meter test with everything off. If the meter moves, there is a leak. If it holds still, check habits, irrigation and a possible meter reading error with the utility.
We try not to. We trace first and open the smallest spot needed to repair.
In South St. Paul, the property owner is responsible for the service line from the building to the main. The city maintains the main.
Yes. We isolate units and risers, and see commercial plumbing for larger properties.
We locate the split, shut off the section and repair it. In unheated spaces we also look at insulation or heat trace to prevent a repeat.