Weak, dribbling taps and a shower that has lost its push are among the most common plumbing complaints we hear from Cape Town homeowners. Low or dropping water pressure is annoying, but it is also a useful warning sign, because the cause is sometimes something that needs attention before it gets worse. Here is a rundown of why water pressure drops, from the harmless to the serious, and how to tell which is which.
It is affecting the whole area
Before assuming the problem is in your home, check whether your neighbours are affected too. Municipal supply pressure can dip during periods of high demand, maintenance or repairs to the network, and in some areas it varies naturally with elevation and time of day. If a whole street has low pressure at once, the cause is usually on the supply side rather than in your plumbing, and it often resolves on its own. If it is only your home, though, the problem is closer to home.
A hidden leak somewhere in your system
One of the more important causes to rule out is a leak. When water is escaping from a pipe somewhere, underground, behind a wall or under a slab, less of it reaches your taps, and pressure drops as a result. A leak large enough to affect pressure is also quietly running up your water bill and potentially damaging your property. If your pressure has fallen and you notice damp patches, an unexplained jump in your water bill, or the sound of running water when everything is off, treat a leak as a real possibility and have it investigated. Finding and fixing hidden leaks is exactly what our leak detection and plumbing repair work is for.
Corroded or blocked pipes
In older Cape Town homes with original galvanised steel plumbing, the inside of the pipes gradually corrodes and scales up over the decades. That build-up narrows the bore the water flows through, steadily choking your pressure and flow. It tends to affect the whole house and gets worse over time rather than suddenly. The lasting fix is to replace the affected galvanised sections with modern copper or PVC, which restores proper flow and removes the ongoing risk of those old pipes leaking or bursting.
A partly closed valve
Sometimes the answer is refreshingly simple. If your main stopcock or an isolation valve is not fully open, perhaps after recent plumbing work, it will throttle your pressure. It is worth checking that your main stopcock is turned fully open before assuming the worst. A valve that has been knocked or left partly closed is one of the easiest pressure problems to fix.
A faulty pressure-reducing valve
Many homes have a pressure-reducing valve fitted to protect the plumbing from excessively high municipal pressure. These valves are a good thing, but like any component they can fail, and when one fails or is set too low, it can leave you with weak pressure throughout the house. A plumber can test and adjust or replace the valve to restore the correct, safe pressure. This is a common and very fixable cause of a whole-home pressure drop.
Blocked aerators, showerheads or fittings
If the pressure problem is limited to one tap or shower rather than the whole house, the cause is often local. Mineral deposits and grit build up in tap aerators and showerheads over time, restricting the flow. Unscrewing and cleaning or replacing the aerator or showerhead frequently brings a single outlet back to life. It is always worth ruling this out for an isolated pressure problem before looking further.
Hot-water-side and geyser issues
If your pressure is fine on the cold side but weak only on the hot, the issue is likely on the hot-water system. Scale build-up in an ageing geyser, or a problem with the geyser’s valves, can restrict hot-water flow specifically. If you are noticing weak hot water along with other geyser warning signs, it is worth having the unit checked, our geyser services can diagnose and sort it.
How to work out what is going on
You can narrow the cause down with a few simple checks. Is it the whole house or one outlet? Cold, hot or both? Did it drop suddenly or fade over months? Are the neighbours affected? Is there any sign of a leak? A gradual, whole-house decline in an older home points toward corroded pipes or a failing valve; a single weak tap points to a blocked aerator; a sudden drop with signs of dampness points to a leak. If your checks do not reveal an obvious, simple cause, or if you suspect a leak, it is time to bring in a plumber, because the underlying problem may be one that quietly worsens and costs you money.
Get your pressure sorted
Low water pressure is sometimes a quick fix and sometimes a symptom of something that genuinely needs attention. Either way, you do not have to live with disappointing showers and slow-filling baths. If the simple checks have not solved it, book an inspection through the form on our site and one of our licensed Cape Town plumbers will find the real cause and put it right.
When low pressure needs a plumber
As a rule of thumb, call a professional if the pressure drop affects your whole home and has been getting steadily worse, if it is weak on the hot side only, if you have ruled out the simple causes like a partly closed valve or a blocked aerator, or if there is any sign of a leak such as damp patches, a rising water bill or the sound of running water when everything is off. These point to causes, corroded pipes, a failing pressure valve, a hidden leak or a geyser fault, that need proper diagnosis and repair rather than guesswork. Catching them early is almost always cheaper than leaving them, since a leak or corroding pipe only gets worse with time.
