IS 1172:1993 is the Indian Standard (BIS) for code of basic requirements for water supply, drainage and sanitation. This code lays down the basic requirements for water supply, drainage, and sanitation in buildings. It provides essential per capita water consumption norms and specifies the minimum number of sanitary fitments required for different types of occupancies.
Stipulates basic requirements for water supply, drainage, and sanitation facilities in buildings to ensure hygiene and public health.
Key per-capita demands, fixture units, pipe sizes, and septic tank dimensions for water supply and sanitation design.
| Reference | Value | Clause |
|---|---|---|
| Water Supply (Urban, >100k pop)— For communities with full flushing systems. | 200 lpcd | Cl. 3.2.1.1 |
| Water Supply (Urban, 20k-100k pop)— For communities with full flushing systems. | 150 lpcd | Cl. 3.2.1.1 |
| Water Supply (LIG/EWS)— For economically weaker sections and LIG colonies. | 135 lpcd | Cl. 3.2.1.1 (Note 1) |
| Peak Factor (Water Demand, >200k pop) | 2.5 | Cl. 3.2.2 |
| Peak Factor (Water Demand, 50k-200k pop) | 3.0 | Cl. 3.2.2 |
| Firefighting Water Demand— P = Population in thousands. This is the total quantity required. | 100 * √P kL | Cl. 3.2.1.2 |
| Min. Residual Pressure (at Ferrule)— Minimum pressure at the connection point to the water main. | 7 m head | Cl. 3.3.1 |
| WC Flushing Cistern Capacity— For single flush cisterns. | 10 ± 0.5 litres | Cl. 5.4.1.1 |
| Urinal Flushing Cistern Capacity— For one urinal bowl. | 5 litres | Cl. 5.4.1.2 |
| Min. Trap Seal (Non-self-cleansing)— For floor traps, etc. | 50 mm | Cl. 5.5.2.1 |
| Min. Trap Seal (Self-cleansing)— For water closets (WCs). | 25 mm | Cl. 5.5.2.1 |
| Fixture Units (WC, Public) | 4 | Cl. 6.4.1 (Table 2) |
| Fixture Units (Wash Basin, Public) | 1 | Cl. 6.4.1 (Table 2) |
| Min. Soil Pipe Diameter | 100 mm | Cl. 6.2.2.1 (Table 1) |
| Min. Waste Pipe Diameter (Kitchen Sink) | 40 mm | Cl. 6.2.2.1 (Table 1) |
| Min. Vent Pipe Diameter | 50 mm | Cl. 6.5.1.1 |
| Min. Slope for Horizontal Drain (100mm) | 1 in 40 | Cl. 6.3.1 |
| Min. Distance (Septic Tank to Water Source)— From any source of drinking water like well, stream, etc. | 15.2 m | Cl. 8.1.3 (Table 3) |
| Min. Distance (Soak Pit to Water Source)— From any source of drinking water like well, stream, etc. | 15.2 m | Cl. 8.1.3 (Table 3) |
| Min. Septic Tank Width | 750 mm | Cl. 8.2.3 |
| Min. Septic Tank Liquid Depth | 1000 mm | Cl. 8.2.3 |
| Min. Septic Tank Freeboard | 300 mm | Cl. 8.2.3 |
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Minimum Domestic Water Demand | 200 litres/capita/day (for communities with full flushing systems). | Calculated based on Water Supply Fixture Units (WSFU), not a per capita rate for pipe sizing. | IPC 2021 |
| Minimum Slope for 100mm (4") Drain Pipe | 1 in 40 (2.5%) to 1 in 80 (1.25%). | 1/8 inch per foot (approx. 1:96 or 1.04%). | IPC 2021 |
| Minimum Trap Seal Depth | 50 mm (25 mm permissible for upper floors subject to approval). | 2 inches (51 mm) minimum, 4 inches (102 mm) maximum. | IPC 2021 |
| Minimum Vent Stack Diameter | 50 mm. | Not less than 1.25 inches (32 mm) and not less than one-half the diameter of the drain served. | IPC 2021 |
| Minimum Water Closet (WC) Drain Size | 100 mm for soil pipes. | 3 inches (76 mm). | IPC 2021 |
| Maximum Spacing for Cleanouts/Manholes | 30 metres (for manholes in straight runs). | 100 feet / 30.5 metres (for cleanouts on horizontal drains). | IPC 2021 |
| Recommended Max Water Supply Velocity | Not to exceed 2.4 m/s in buildings. | Design practice is typically 1.5 - 2.4 m/s (5-8 ft/s) to prevent noise and erosion. | ASPE Plumbing Engineering Design Handbook |