Supply cut announced?

Will your water last?

Chennai Metro Water announces cuts for pipeline work, and summers mean tankers. Tell the auto anna how many of you there are and what you've stored. He works out how many days it lasts, the day you'd run short, and what to do before the cut starts.

People at home

Supply cut

days

Normal use per person

L / day

Default 135 L: the CPHEEO norm for Indian cities. Change it if you know your building's use.

Storage, quick fill

Sump (your share)

Overhead tank

Drums, cans, buckets

One bucket ≈ 15 L. 10 buckets = 150 L.Tanker size

Nothing you type leaves your phone. This is arithmetic, not a forecast of when supply will fail.

Short at normal use

3.7 days

2,000 L stored ÷ 540 L a day (4 × 135 L).

"At normal use, you run dry on day 4 of 4."

Day by day, at normal use

Dark-bordered days are the cut. Blue is water left at the start of each day.

Normal (135 L/person)

3.7 days

0.3 days short

Essentials (60 L/person)

8.3 days

covers the cut

Bare minimum (15 L/person)

33.3 days

covers the cut

Short by 160 L at normal use; on essentials only you get through.

What to do

At normal use you run out on day 4 of 4. Switch to essentials only (about 60 L per person a day) from day 1.
Essentials: drinking and cooking first, one bucket bath each, flush with used bathing water, wash dishes in a basin.
Run the washing machine and wash the car or bike only after supply returns.
Ask your building or RWA whether the sump is cleaned before and after a long cut.

Norms: 135 L/person/day is the CPHEEO Manual on Water Supply norm for Indian metropolitan cities; 15 L/person/day is the Sphere Handbook emergency minimum for drinking, cooking and basic hygiene; 60 L/person/day is our “essentials only” day (one bucket bath, bucket flushing, cooking, drinking, dishes). Your real use depends on your building.