WOH Water Main Leak Repair Guide

Early detection and prompt repair of water main leaks are critical compliance and public health obligations. Visible leaks may present as wet ground, sinkholes, or pressure drops; non-visible leaks require systematic isolation and flow monitoring or acoustic detection equipment. For small systems, closing isolation valves section by section while monitoring pump runtime identifies the affected zone, then walking the alignment to listen for hissing or probing wet soil pinpoints the leak location. Before excavating, isolate the smallest section containing the suspected leak using your system map, confirm valve positions, notify customers, and document all isolation steps.

Water main repair work involves excavation, pressurized systems, and hazardous chemicals, all governed by OSHA standards. Any excavation 5 feet or deeper requires proper shoring or a trench box, and soil must be classified by a competent person—never enter an unshored trench in Type B or C soil. Call 811 before digging. The main must be fully isolated and depressurized before cutting or removing fittings; open air release valves to vent trapped pressure. Chlorine disinfectants (calcium hypochlorite and sodium hypochlorite) are oxidizers requiring nitrile gloves, safety glasses, and chemical-resistant clothing; never mix calcium hypochlorite with other chemicals, and work only in well-ventilated areas.

Repair method depends on pipe material, failure type, and main diameter. Point leaks in straight runs are typically repaired with full-circle stainless steel repair clamps sized to the pipe's outside diameter, not nominal size. Larger damage requires cut-out repair with a replacement spool and mechanical couplings—use restrained couplings near bends, tees, or end caps where thrust forces exist. Service saddle and corporation stop leaks usually require replacing both components together rather than threads alone. Restrained couplings and tie-rod assemblies provide temporary thrust restraint; permanent repairs may require thrust blocks per your system's design standards.