Why Is My Water Pressure Low?
Low water pressure is commonly caused by underground water line issues — leaks, corrosion, partial blockages, or failing pressure regulators. Sloan Underground Construction locates and repairs these problems using trenchless methods that protect your yard and restore full pressure in one to two days. Most residential repairs cost $800 to $2,200; full waterline replacements run $1,800 to $4,500.
Get a Free DiagnosisSloan Underground Construction is a licensed South Carolina contractor based in Greenville, serving the Upstate, Midlands, and Western North Carolina since 1965. We diagnose and repair low water pressure caused by underground water line problems — leaks, corrosion, blockages, and failing regulators. Same-day response is available for emergency pressure loss.
Common Reasons Water Pressure Drops
Low water pressure is rarely random. Here are the five most common causes we find when diagnosing pressure loss across the Carolinas.
Underground Water Line Leak
A crack or break in the service line between your meter and home allows water to escape into the soil before reaching your fixtures. Even a small leak significantly reduces pressure. Signs include soggy yard spots, higher water bills, and the sound of running water when all taps are off.
Corroded or Aging Pipes
Galvanized steel pipes installed before 1970 corrode from the inside out, narrowing the flow path and reducing pressure systemwide. Rust deposits restrict water flow even when the pipe hasn't fully failed. Replacement is the permanent fix.
Partial Blockage / Sediment Buildup
Mineral deposits, sediment, or debris accumulate inside the waterline over decades, restricting flow. This is especially common in areas with hard water or iron-rich municipal supplies. Flushing or pipe replacement clears the blockage.
Faulty Pressure Regulator
The pressure-reducing valve (PRV) near your meter can fail, dropping house pressure well below the incoming municipal supply. Testing the pressure before and after the regulator identifies this quickly. Regulator replacement typically costs $300 to $600.
Municipal Supply Issue vs. Private Line Issue
If neighbors on your street have normal pressure, the problem is on your property — usually the underground service line. If the entire street has low pressure, it's a municipal supply issue; call your water provider. Check with neighbors first to rule out a system-wide drop.
How Sloan Underground Diagnoses and Repairs Low Water Pressure
Pressure Test & Leak Detection
We measure static pressure at the meter and inside the home to identify where pressure is being lost. If a leak is suspected, we use electronic leak detection equipment to pinpoint the underground break without excavation.
Underground Line Inspection
For corrosion or blockage issues, we inspect the underground line using camera equipment or electronic locating tools. This reveals the condition of the pipe interior and identifies whether repair or full replacement is needed.
Trenchless Repair or Targeted Excavation
Single leaks are repaired with targeted excavation at the break point. Widespread corrosion or multiple failures require full waterline replacement — done trenchless with horizontal directional drilling to protect your yard. We restore full pressure and test before backfilling.
Frequently Asked Questions About Low Water Pressure
Why is my water pressure suddenly low?
Sudden water pressure loss is most often caused by an underground water line leak, a failing pressure regulator, or a partial blockage in the service line. Less commonly, it's a municipal supply issue affecting your street. If your neighbors have normal pressure, the problem is on your property — typically the underground pipe between the meter and your home.
How do I know if an underground pipe is leaking?
Signs of an underground water line leak include persistently low pressure across all fixtures, soggy or sunken spots in your yard (even during dry weather), an unexplained spike in your water bill, or the sound of running water when all taps are off. We use electronic leak detection and pressure testing to locate underground leaks without excavation.
Can a broken underground line cause low water pressure?
Yes. A cracked, corroded, or partially collapsed underground water line restricts flow and causes systemwide pressure loss. Even a small leak can drop pressure significantly because water escapes into the soil before reaching your fixtures. Repairing or replacing the damaged section restores full pressure.
How much does it cost to fix low water pressure from a pipe leak?
Repairing a single underground leak typically costs $800 to $2,200 depending on depth and location. If the line has multiple problems or is corroded throughout, full waterline replacement is more cost-effective — usually $1,800 to $4,500 for residential properties. We provide a free written estimate after diagnosing the issue.
How long does underground water line repair take?
Most underground water line repairs are completed in one day. Trenchless leak repairs often finish within 4 to 6 hours. Full waterline replacements using horizontal directional drilling typically take one to two days depending on line length and site conditions. We provide a timeline estimate before starting work.
Last Updated: August 2026