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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.
Quick Reference — Top IS 1172:1993 Values
Key per-capita demands, fixture units, pipe sizes, and septic tank dimensions for water supply and sanitation design.
✓ Verified 2026-04-27
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
⚠ Verify against the latest BIS/IRC publication and project specifications. Amendment Slips may modify values.
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! The 135 lpcd requirement for LIG housing comprises 90 liters for domestic use and 45 liters for flushing.
! When computing total water demand for large projects, always account for firefighting, HVAC makeup water, and landscaping separately, as IS 1172 baseline values primarily cover domestic needs.
! Population estimates for office buildings should be based on actual seating or 1 person per 10 square meters of floor area if exact layouts are unknown.
Consolidated list per BIS. For the text of each amendment, refer to the BIS portal link above.
waterdrainage pipessanitary fixtures
International Equivalents
Similar International Standards
IPC 2021ICC (International)
HighCurrent
International Plumbing Code
Comprehensive code for water supply, drainage, venting, and fixtures inside buildings.
AS/NZS 3500 SeriesStandards Australia / Standards New Zealand (AU/NZ)
HighCurrent
Plumbing and drainage
A series of standards forming a comprehensive plumbing and drainage code for Australia/NZ.
BS EN 806 & BS EN 12056BSI (UK) / CEN (Europe)
MediumCurrent
Specification for installations inside buildings conveying water for human consumption & Gravity drainage systems inside buildings
Together, these European standards cover water supply and drainage systems within buildings.
UPC 2021IAPMO (US)
HighCurrent
Uniform Plumbing Code
Comprehensive code for plumbing installations, an alternative to the IPC in many US jurisdictions.
Key Differences
≠Water demand calculation: IS 1172 uses a prescriptive per-capita consumption rate (e.g., 135-200 litres per capita per day) for design. The International Plumbing Code (IPC) uses a detailed 'Water Supply Fixture Unit' (WSFU) method, which calculates probable demand based on the number and type of fixtures, offering a more tailored sizing approach for building-specific loads.
≠Drainage and Vent Sizing: The IPC employs a highly detailed 'Drainage Fixture Unit' (DFU) system to size drainage pipes and the corresponding vent system. IS 1172 relies on simpler tables based on the number of fixtures and provides basic minimum diameters, lacking the granular, engineered approach of the IPC.
≠Venting System Requirements: The IPC specifies a complex and comprehensive set of venting requirements (e.g., circuit vents, loop vents, wet vents, air admittance valves) to protect every trap seal. IS 1172's requirements are much more fundamental, focusing primarily on a main vent stack and its connection, without the same level of detail for branch venting.
≠Modern Technologies: Being from 1993, IS 1172 does not address modern plumbing technologies. Current international codes like the IPC include detailed provisions for water-saving fixtures, greywater recycling systems, and engineered solutions like Air Admittance Valves (AAVs).
Key Similarities
≈Fundamental Health Principles: Both IS 1172 and international codes share the same core public health objectives: to provide safe, potable water free from contamination and to remove wastewater and sewage hygienically.
≈Mandatory Use of Traps: Both Indian and international standards mandate the use of water seal traps at every plumbing fixture to create a barrier against the entry of harmful and noxious sewer gases into occupied spaces.
≈Gravity-Based Drainage: The primary mechanism for drainage in both codes is gravity. They both specify minimum gradients (slopes) for horizontal drainage pipes to ensure self-cleansing velocities that transport solids effectively.
≈Requirement for System Venting: Despite differences in complexity, both standards recognize the absolute necessity of venting the drainage system to the atmosphere. This prevents the siphoning or blowing out of trap seals due to pressure fluctuations within the system.
≈Separation of Drainage Systems: Both codes require that sanitary drainage (from toilets, sinks, etc.) and stormwater drainage (from roofs, paved areas) be installed as separate systems to prevent overloading of sewage treatment plants during rainfall.
Parameter Comparison
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).