A water tank leak is more than an inconvenience — constant water pressure against a cracked wall accelerates the damage every single day it goes untreated, and if the tank supplies drinking water, corrosion products and contamination become genuine health concerns.
Overhead tanks typically leak at construction joints, corners, or around inlet and overflow pipe penetrations. Because they hold a relatively shallow water column, the hydrostatic pressure is manageable, and repairs usually involve cleaning, crack repair, and application of a food-grade cementitious or polymer coating safe for potable water storage.
Underground tanks face a tougher challenge: constant hydrostatic pressure from groundwater outside pushing in, in addition to the water pressure from inside. These tanks need a system engineered for continuous pressure from both directions, and we typically specify a heavier-duty cementitious slurry system with reinforced detailing at all corners and joints.
Age matters. A tank over 15 years old has usually seen enough freeze-thaw and thermal cycling that a full internal recoat, rather than a spot repair, is the more economical long-term choice — patch repairs on old concrete tend to fail again within a year or two as the surrounding material continues to deteriorate.
Whichever type of tank you have, always confirm the coating used is rated safe for drinking water contact if the tank supplies household water — not every waterproofing product is, and this is a detail worth asking your contractor directly.