Water Line Replacement in Longmont: Leaks, Pressure and the Meter

Yard, meter box or inside: where the leak sits

Signs of a service line leak include a wet or unusually green patch above the line, a meter that keeps turning with everything off, a bill that climbs for no reason, and low pressure through the whole house. Hissing near the shutoff or a damp meter box point to the connection points.

A leak between the meter and the house sits on the customer side, so it is found and repaired from the yard. The leak detection page explains how plumbers confirm a hidden leak before digging, and the dispatcher can send someone to trace it.

• Meter box full of water: a leak at the meter connection, or runoff entering the box.
• Soggy lawn strip in dry weather: a leak along the line, often between the box and the foundation.
• Pressure drops at every tap: a major leak, a partly closed valve or a failing regulator.
• Bubbles through concrete, seepage or a swampy patch: water finding its way up from a leaking line.
• Sudden jump in the bill: check the meter with fixtures off before assuming the worst.

For an after-hours emergency involving a water meter, the City of Longmont says to call Longmont Police Dispatch. The city also replaces residential meters on a scheduled cycle through a maintenance program, so a meter swap on your street does not by itself mean a problem.

Locating the line before any digging starts

Colorado law requires a call to Colorado 811 before you dig, even for a small hole. Both Colorado 811 and the City of Longmont say to make the request at least three business days ahead, by phone at 811 or online. Utility owners then mark their buried facilities.

That service covers public utilities. A private line, such as a branch to a shed or a yard hydrant, is not marked by the utilities, and Colorado 811 points to private locate companies for those. Marks last 30 days or until they fade, and fresh marks are needed if they are lost.

Repair, replace or sleeve the line

Repair makes sense for one failure in sound pipe. Replacement makes sense when the line has failed more than once or is made of a material that is wearing out. The options are an open trench, a trenchless method that pulls a new line through the old path, or a partial replacement from the meter box to the foundation.

One local question is lead. The City of Longmont's 2025 water quality report states that all water service lines in the city can be classified as non-lead, following an inventory finished in 2024. So the reason to replace a line here is wear and leaks, not lead.

Shutoff valves and testing the line

A main shutoff that will not close is a hidden hazard, since it is the first thing you reach for in a burst pipe. Old gate valves seize with age, and a stiff valve can break when forced. Replacing it during a planned visit costs less than doing it mid-flood. Exercise the valve gently once or twice a year and note which way it turns.

When the work is done, the new line is pressure tested, which means holding it under pressure and watching for any drop. The test catches a poor joint before the trench is filled in, and it is part of why a repaired line is reliable.

Yard drainage is a separate question. A requested yard drain cleaning belongs with drainage work and the drain cleaning page covers the household side, but grading and exterior drainage are not part of water line repair.