Water calculator

How much water does your home need to get through an outage?

Move the sliders. The recommendation updates as you go. It's a starting point, and the site visit confirms it.

What is it mainly for?

Backup during outages Rainwater for the garden

People in the home

How carefully will you use water during an outage?

Essentials only · 50 L Careful · 100 L As normal · 150 L

Litres per person per day. 50 L covers drinking, cooking, a bucket wash and some flushing. 100 L allows short showers.

Days you want to be covered

3 days

Many Tshwane outages last one to three days, and reservoirs often take longer to recover after repairs.

Also important to you

Safer drinking water Low mains pressure It's a business

Roof area for rain harvesting

150 m²

A typical 3-bedroom house has 150–220 m² of roof. Use the footprint, not the slope.

Recommended tank 5 000 L Gives you 11.3 days at your chosen use.

Suggested package

A mains-fed tank with a pump and automatic changeover keeps taps, showers and toilets running.

Installed, from R18 000

Tank	Days at your use	Days at 50 L

We count 90% of a tank as usable, because the outlet sits above the floor.

Your roof

Rain your 150 m² roof can collect

About 80 000 L a year, but only 6 000 L from May to September, when the big maintenance shutdowns happen.

Wet months Dry months (May–Sep) 2026 maintenance window

Based on approximate long-term average rainfall for Pretoria (about 670 mm a year) and 80% of roof rain reaching the tank.