Code of practice for water supply in buildings
1983 Edition

IS 2065 recommends a range of pipe materials depending on water supply conditions: Cast iron (both vertically and centrifugally cast) for durability; steel pipes with protective coatings such as bitumen or cement mortar to combat corrosion; reinforced and prestressed concrete pipes for large diameter and underground use; galvanized mild steel tubes for moderately corrosive environments; copper and brass for corrosion resistance in specific applications; wrought iron historically used but now less common; asbestos cement for non-corrosive water and lightweight applications; lead pipes are generally discouraged for potable water due to toxicity, limited to flushing or overflow with protective wrapping; polyethylene and unplasticized PVC pipes are preferred for lightweight, corrosion-resistant potable water systems, with jointing per relevant IS standards. Key factors influencing material choice include water chemistry, soil corrosiveness, cost, expected lifespan, and corrosion resistance requirements.

To prevent contamination of storage tanks as per IS 2065, construction should use durable materials such as iron, wrought iron, mild steel plates, or reinforced cement concrete ensuring watertight integrity without putty. Tanks should have smooth internal surfaces, proper drainage, and be positioned so that underground tanks extend at least 30 cm above the highest flood level or have manhole covers raised accordingly. Covers must be dust, light, and mosquito-proof with locks, and manholes should have hinged, leakproof cast iron covers. Valve fittings include ball valves positioned to avoid submersion and stop valves at outlets. Maintenance involves regular inspections for corrosion and leaks, emptying and wire-brushing tanks showing corrosion without scraping, applying inert anti-corrosive paint that does not affect taste or odor, plugging outlets during cleaning to prevent debris ingress, and ensuring proper drainage to avoid water pooling around tanks.

IS 2065 advises that sizing communication and service pipes requires data such as maximum flow rate, pipe length, frictional head loss, and internal roughness. Elevation differences and main pressure should be accounted for, along with losses from fittings like bends and valves per IS 2951 Part 2. Service pipes 50 mm bore or larger must connect to mains via special T-branches, while smaller pipes use special branches if the main bore is less than or equal to three times the service pipe diameter. Entry depth must be at least 0.75 meters below ground level, with sleeves through the building structure filled with bituminous or other suitable sealing materials. Nominal diameters refer to internal diameters unless otherwise specified. These guidelines ensure proper hydraulic performance and protection of service connections.

Disinfection per IS 2065 involves thoroughly flushing tanks and pipes with clean water initially. The tank is then refilled while gradually adding chlorine disinfectant to ensure uniform mixing, aiming for a chlorine concentration of 50 ppm. When using bleaching powder, 150 grams per 1000 liters of water is recommended, prepared to a creamy consistency before addition. After filling, supply is stopped and taps are opened progressively until the chlorine odor is detected, then closed sequentially. The tank is topped up with chlorinated water and kept charged with disinfectant for at least three hours. Finally, the entire system is flushed thoroughly before use. This process ensures elimination of microbial contaminants and safe potable water supply.

IS 2065 specifies that water supply pipes must not share trenches with sewer or drainage lines. If unavoidable, the water pipe must be positioned at least 30 cm above the sewer pipe and placed on a solid shelf within the trench to prevent contamination. The number of joints in water pipes should be minimized, and all pipes and joints must be durable and leak-proof to withstand environmental stresses. Cross-connections between potable and impure water systems are strictly prohibited; valves cannot replace this requirement. Additionally, an air gap of at least twice the pipe diameter or 150 mm minimum must be maintained above cistern edges when mixing or providing alternative water supplies to prevent backflow. Service pipes must be independent from distribution pipes to avoid backflow contamination.