Low Water Pressure in Wellington
Low shower flow
A trickling shower is the most common complaint in Wellington homes built before the 1990s. Our low shower pressure page is very popular. Most are running an old low-pressure hot water system — maximum pressure around 7.6m of head (76 kPa) — paired with narrow-bore galvanised or Polybutylene pipes that have corroded from the inside in the case of galv or the pipe size is too small for low pressure. Small bore pipes is what you likely get for that low price you accepted. Often low pressure is not the problem. Small bore is the issue. Which ever it is replacing the pipe with a larger size and make it copper can solve low flow issues in the shower.
The fix depends on the cause. Southern has been solving this for 40+ years across Karori, Khandallah, Johnsonville and the Hutt Valley. Call 0800 484 353 and we’ll diagnose it before we quote.
Low, High or Mains Pressure — What’s the Difference?
Low water pressure systems are often fed by a header tank in the ceiling. Gravity pressure systems from ceiling tanks is limited to the water level in the tank down to its outlet rose in the shower which can often be 1m of head that is 10kPa in the case of a 1m height — enough for a shower but not a powerful one. You can spot them: a small tank in the ceiling cavity, slow-filling cisterns, and a cylinder without a pressure-reducing valve.
Pressure Reducing Valves
Often have Low Water Pressure
Pressure reducing valves can also be the cause of low shower flows where the vent pipe is short ie the height from the shower rose to the water in the vent pipe might only be 2m thats 20kPa, still not much compared to 500kPa from a high pressure hot water cylinder. But if the pipes are sized correctly, 20mm copper a good shower flow can be had.
High / mains pressure feeds directly from the incoming water supply — usually 500 kPa after the pressure-limiting valve (network can reach 1000 kPa and more). You get punchier showers, faster cistern filling, and the freedom to use modern tapware designed for mains pressure.
A high-pressure mixer won’t work well on a low-pressure system — the small ports restrict flow and you’ll get even less shower flow. Matching the mixer to the system is step one.
Seven Ways to Improve Low Shower Pressure
Rough budget ranges — we always quote fixed-price after a diagnostic visit:
- Change the shower rose — $350–$650. Sometimes the rose is the restriction, not the pipework.
- Change the shower mixer — $800–$1,900. Matches the mixer to your system pressure.
- Upgrade cold supply to mains + mixer change — $800–$1,900.
- Install a booster pump — $1,400–$2,600. Good if the rest of the system is sound, but is not the same fix as a mains pressure hot water cylinder.
- Pressure-reducing valve system — $2,800–$3,800.
- Replace with a valve-vented system — $5,485–$7,900.
- Upgrade to a high-pressure hot water cylinder — $4,200–$7,600. See our hot water cylinder page.
When the Answer is a Full System Swap
If the hot water cylinder is ageing or the house needs a full re-pipe anyway, going straight to a modern mains-pressure system is usually cheaper than patching around the old one.
- Gas continuous-flow system — $4,500–$6,000. Endless hot water, mains pressure.
- Heat pump water heater — $9,000–$12,000. Highest efficiency, lowest running cost over 10+ years.
We also replace narrow-bore pipework with larger-bore copper or Pex where the pipes themselves are the bottleneck — particularly in homes still running original Dux QEST or galvanised lines.
Diagnose Before You Buy
We’ve seen people spend $2,000 on a booster pump that didn’t help — because the restriction was in the shower rose. Or they’ve replaced the mixer and gotten worse flow — because they put a mains-pressure unit on a low-pressure system.
Our pressure diagnostic is a small service call: we measure at the meter, at the cylinder, at the shower arm. We tell you where the restriction is, then quote the fix. Serving Karori, Johnsonville, Khandallah and the Hutt Valley with real data, not guesses.
Related Pressure Problems
Low pressure often travels with other symptoms. If you’re noticing any of these, call us — it points to a system-level problem, not just a shower issue:
- Hot water running out quicker than it used to
- Kitchen tap flow dropping at the same time as the shower
- Discoloured or rust-tinted water from the hot side
- Unexplained water bills — could be a hidden leak dropping supply pressure
- Banging pipes or water-hammer when taps close
- Toilet cisterns taking 5+ minutes to refill
Call 0800 484 353 — 24/7, every public holiday.
Frequently Asked Questions
Most commonly you’re on a low-pressure (header-tank) system — max 76 kPa — paired with a restrictive shower rose, an undersized mixer, or corroded galvanised pipework. Occasionally it’s a partially closed valve or a hidden leak. Diagnosis is usually a 30-minute service call.
