| Frozen or exposed pipe | Frost on pipe surface, no water flow during sub-freezing weather, dripping in unheated crawl spaces or cantilevered overhangs. | Shut off the main water valve immediately. Open indoor faucets slightly. Never use open flames or blowtorches. | Burst pipe from ice expansion; split copper fitting or cracked PEX crimp. | Immediately if active spraying occurs or pipe fails to thaw safely. |
| Mature-tree root intrusion | Gurgling toilets, slow drainage across multiple ground-floor fixtures, foul sewer odor in yard or basement. | Cease running washing machines, dishwashers, and showers. Avoid corrosive chemical drain cleaners. | Root penetration through joints in vitrified clay, cast iron, or Orangeburg sewer laterals. | Immediately when sewage backs up into basement tubs, floor drains, or toilets. |
| Piedmont clay movement | Repeated sewer clogs following seasonal wet/dry weather transitions, sunken yard depressions, cracked cleanout collars. | Limit household wastewater discharge; check the outdoor sewer cleanout cap for overflow. | Ground shift causing pipe belly, sheared joints, or negative slope in the exterior sewer lateral. | When recurring clogs return after mechanical clearing; schedule a camera inspection. |
| Heavy-rain hydrostatic pressure | Sump basin water rising rapidly, pump motor humming continuously, damp baseboards or floor seam seepage. | Check exterior discharge line for blockages; verify float switch movement; activate battery backup pump if power is out. | Sump pump mechanical failure, stuck check valve, or foundation drainage overwhelmed. | As soon as the pump fails to evacuate the basin during severe rainfall. |
| Aging galvanized or copper pipe | Rust-colored water, gradual loss of pressure throughout the house, pinhole sprays behind finished walls. | Isolate the leaking fixture or branch valve; check water meter movement while all taps are closed. | Internal pitting corrosion in Type M copper; severe mineral scale calcification in galvanized iron. | Promptly when damp wall spots appear or static pressure drops below 40 PSI. |