JoJo Tanks and Backup Water Systems: What to Plan Before You Install One

Water supply interruptions — whether from planned maintenance, infrastructure faults, or unplanned outages — are a fact of life for a lot of households across Midrand, Johannesburg and Pretoria. A backup water storage system means an interruption is an inconvenience rather than a genuine crisis. Here’s what to actually think through before installing one.

What a JoJo Tank System Actually Involves

A “JoJo tank” (the brand name has become the generic term, much like “geyser”) is a large polyethylene water storage tank, typically ranging from around 750 litres for a small household top-up to 5,000 litres or more for a property that wants several days of backup. On its own, a tank just stores water — to actually use that water at normal household pressure, you generally need to add a pressure pump and a changeover system that switches between municipal supply and tank water automatically (or manually, depending on setup).

Key Decisions Before You Install One

1. Tank Size

This comes down to how many people are in the household and how long you want to be covered for. As a rough guide, an average household uses somewhere in the region of 200-300 litres per person per day for normal use — though that drops significantly if you’re deliberately conserving water during an outage (no long showers, no garden watering, minimal laundry). A 2,500L tank gives a family of four a few days of conservative backup; larger tanks obviously extend that.

2. Filling Method

Most systems fill automatically from the municipal line whenever supply is available, using a float valve the same way a toilet cistern works — the tank simply tops itself up and sits full, ready for the next interruption. Some households also plumb in gutter downpipes to supplement with rainwater, though for drinking-quality backup water you’d want filtration in that line too.

3. Automatic vs. Manual Changeover

A manual system means you physically switch a valve when the municipal supply drops — simple and cheaper, but only useful if someone’s home and paying attention when it happens. An automatic changeover system detects the pressure drop and switches to tank water without anyone doing anything, which matters if you’re not always home when outages happen.

4. Pump Sizing

Without a pump, tank water only reaches taps below the tank’s own height via gravity — fine for an outside tap, not enough for normal indoor pressure in most homes. A correctly sized pressure pump is what makes tank water behave like normal mains pressure at every tap in the house, including upstairs. Undersizing the pump is a common mistake that leaves people with working backup water that barely trickles out.

Where to Position the Tank

Tanks need a stable, level base — usually a compacted sand or concrete pad — and enough clearance for the plumbing connections and any future maintenance. Elevating a tank on a stand adds gravity-fed pressure as a bonus, though most residential setups still rely on a pump either way. Local council rules in some areas also have restrictions on tank placement relative to boundary walls, so it’s worth checking before assuming a spot is fine.

Getting the Plumbing Right

The part that actually determines whether a backup system works well or badly is the plumbing integration — how the tank, pump, and changeover valve tie into your existing supply line, and whether backflow prevention is correctly installed so tank water can never contaminate the municipal line (a real requirement, not just good practice). This is where a proper installation matters more than the tank itself; a poorly plumbed system with an expensive tank still performs badly.