Johannesburg43 of the city’s 129 reservoirs are leaking.
The city opened one replacement while admitting 48.7% of treated water never reaches a tap — 26.3% lost to leaks, Johannesburg Water said.
Repairing all 43 costs R1.25 billion, Johannesburg Water said; the utility can afford only 15 next year.
Sources: Daily Maverick
NON-REVENUE WATER
The industry term for water a utility treats but never bills is non-revenue water — a mix of physical leaks, metering errors, and unbilled use. Well-run systems hold this below 15%; Johannesburg's 48.7% means nearly half the energy and chemicals spent on treatment is wasted before a tap turns.
WHY PIPES FAIL ON A SCHEDULE
Cast iron mains laid in the early 20th century have a 80–120 year design life; asbestos cement from the 1950s–70s lasts 50–70 years. Every major city built on a wave of pipe-laying inherits a wave of pipe-failures decades later. Johannesburg's reservoir stock dates largely to the apartheid-era buildout of the 1960s–80s, now arriving at end-of-life simultaneously.
THE PRESSURE PARADOX
Higher water pressure means more leakage — flow through a crack scales with the square root of pressure. Utilities with chronic leaks often deliberately reduce pressure at night, accepting weaker showers in exchange for less loss. Johannesburg's hilly topography forces high pressures in low-lying suburbs, accelerating failures there.
THE REPLACEMENT MATH
Johannesburg Water can fund 15 of 43 reservoir replacements next year — roughly a third. At that pace, today's backlog takes three years to clear, while the rest of the 1960s-era stock keeps aging into the queue. This is the structural pattern of infrastructure deficit: the repair rate is slower than the decay rate.
WHO LOSES WATER LAST
When a utility cannot supply everyone, it sheds load by geography. Wealthy suburbs with backup tanks, boreholes, and political voice are cut last; townships with no storage are cut first. South Africa's 'Day Zero' planning in Cape Town (2018) made this hierarchy explicit. Johannesburg's leak crisis follows the same logic — the same neighborhoods that lost water during 2024's outages will lose it again.
THE FISCAL TRAP
A utility that loses half its water collects revenue on only half — but pays full cost to treat all of it. The shortfall is filled by tariff hikes on paying customers, which incentivizes them to install boreholes and exit the system, which shrinks the revenue base further. Detroit's water utility entered this spiral in the 2000s; Johannesburg's tariff trajectory follows the same curve.