Plumbing & Water Supply

Plumbing is the system of pipes, valves, and fixtures for water supply, distribution, and waste removal in buildings. Indian Standards: IS 1172 (water supply), IS 778 (gunmetal valves), IS 1701 (cast-iron pipes), IS 1239 (steel tubes), IS 4985 (uPVC pipes), IS 2982 (PVC), and the Council of Architecture / Indian Plumbing Skills Council professional norms. The dominant piping materials in modern Indian construction: (1) GI (galvanized iron) — older, decreasing market share due to scaling; (2) PVC and uPVC — most common for cold water and drainage; (3) CPVC — increasingly common for hot water; (4) PPR (polypropylene random copolymer) — premium hot/cold water; (5) Copper — high-end residential and commercial.

Water supply system: (1) Source — municipal supply (typical Indian residential), borewell, tanker. (2) Main intake to building — typically 25-32 mm dia GI or PVC at street level. (3) Storage — underground sump (UGT) typically 3-5 m³ for residential, sized at 24-hour demand per CPHEEO norms (135 LPCD residential, 200 LPCD commercial). (4) Pumping to overhead tank (OHT) — typically 1500-3000 L for residential, providing gravity head for distribution. (5) Distribution — branched piping to fixtures, with minimum 1.5 m head from OHT bottom for adequate pressure. (6) Hot water — solar water heater + PPR hot piping standard for residential.

Waste removal: (1) Soil pipes (110 mm) — toilet wastes (faecal matter and urine); separate from waste-water pipes. (2) Waste pipes (40-75 mm) — kitchen sinks, washbasins, bath drains. (3) Floor drains and traps — at every floor level. (4) Vent pipes — extend through roof to allow gas escape and prevent siphoning. (5) Manholes / inspection chambers at 30 m intervals. (6) Final connection to municipal sewer or septic tank. Common Indian plumbing issue: single-stack drainage (combining soil + waste + vent in one pipe) is not permitted in modern code; separate single-stack-with-secondary-vent or two-pipe systems are required. The most-overlooked aspect: pipe size sizing per fixture units; CPHEEO Manual provides tables — many Indian residential designs are oversized (waste water) or undersized (cold water at peak demand).