What is the maximum flow rate for a 5-star rated basin tap?

The maximum flow rate is 4.0 litres per minute (L/min) at a test pressure of 0.3 MPa (Table 1).

Does this standard apply to kitchen sink mixers?

Yes, the standard covers taps and mixers for washbasins, sinks, and showers (Clause 1).

How is a water-saving tap identified?

Compliant products must be marked with their star rating and maximum flow rate in L/min, along with the BIS Standard Mark (Clause 6).

What is the difference in flow rate between a 3-star and 5-star shower head?

A 3-star shower has a max flow rate of ≤ 10.0 L/min, while a 5-star shower has a max flow rate of ≤ 6.0 L/min, offering significant water savings (Table 2).

IS 17953 Part 4

: 2023

Plumbing Taps and Mixers - Special Technical Specification for Thermostatic Mixer Taps

CurrentFrequently UsedSpecificationBIMMEP · Plumbing Fixtures and Valves

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This standard specifies technical requirements and a star rating system for water-efficient plumbing taps, mixers, and showers to promote water conservation. It classifies fixtures from 1-star to 5-star based on their maximum flow rate at a standard test pressure, enabling easy identification of water economy products.

Specifies special technical requirements for thermostatic mixer taps.

Quick Reference Values

Maximum Flow Rate for 5-Star Tap (Basin)≤ 4.0 L/min

Maximum Flow Rate for 4-Star Tap (Basin)≤ 6.0 L/min

Maximum Flow Rate for 3-Star Tap (Basin)≤ 8.0 L/min

Maximum Flow Rate for 5-Star Shower≤ 6.0 L/min

Maximum Flow Rate for 4-Star Shower≤ 8.0 L/min

Default Star Rating Flow Rate (Basin)≤ 10.0 L/min (2-Star)

Standard Test Pressure for Flow Rate0.3 MPa (3 bar)

Practical Notes

This standard is essential for projects targeting green building certifications (like IGBC, GRIHA) which mandate or award points for using water-efficient fixtures.

The star rating is determined at a test pressure of 0.3 MPa (3 bar). Actual on-site flow rates may differ based on the building's water supply pressure.

Always check for the BIS Standard Mark and the star rating marking on the product or its packaging to ensure compliance and authenticity.