A leaky pipe inside your walls or under your floors can go undetected for months — quietly causing water damage, mold, and structural deterioration. In Northridge and throughout Los Angeles County, where homes are older and water pressure runs high in many neighborhoods, hidden leaks are more common than most homeowners realize. 1. Your Water Bill Has Gone Up With No Explanation Usage habits haven't changed but your bill keeps climbing? Water is going somewhere it shouldn't. A running toilet can waste 200 gallons per day. A small pipe leak inside a wall can waste even more. Don't assume a billing error — investigate. 2. Water Stains on Ceilings or Walls Yellow or brown stains are clear evidence of water coming from above or behind that surface. The stain often appears far from the actual source — water travels along joists and framing before it pools. Don't assume the problem is directly behind where you see the discoloration. 3. Low Water Pressure Throughout the House Pressure drop at one fixture usually means a clogged aerator. Pressure drop throughout the entire house is more serious — it can indicate a significant leak in your main supply line and needs professional inspection. 4. You Can Hear Water Running When Everything Is Off Turn off every faucet and appliance. Go to your water meter — in Northridge it is typically at the street or in a utility box near the sidewalk. Watch the meter. If it is still moving, water is flowing somewhere inside your home. 5. Musty Smell or Visible Mold Mold requires sustained moisture. If you smell it — especially inside cabinets under sinks — water has been present long enough for biological growth. In Southern California's climate, mold inside wall cavities spreads quickly once a slow leak gets started. 6. Soft Spots or Buckling in Your Floor A spongy or visibly buckled floor section means the subfloor has absorbed water — usually from a nearby toilet, dishwasher, or shower base that has been leaking slowly. Common in older Northridge homes, especially those built before 1990. What Does Catching a Leak Early Actually Save? Leak detection: $150–$400. Small pipe repair: $300–$800. Water damage restoration after months of undetected leaking — drywall, insulation, flooring, framing: $5,000–$25,000+. Call when you see the first sign, not the sixth. Multiskill Builders handles leak detection, pipe repair, and full water damage restoration in Northridge, Glendale, Burbank, Pasadena, North Hollywood, and all of Los Angeles County.