Pressure Testing New Water Pipes
How It Should Be Done Before the Walls Close (2026)

What a pressure test is, and what it is not

Every new water supply pipe in a renovation, whether it feeds a new basin, a relocated shower or a whole re-pipe, is joined at dozens of points. Each joint is a place where water can escape. A pressure test loads the finished pipework with water at a pressure higher than it will normally see, then checks that the pressure holds. If it holds, every joint in that section is tight.

It is not the same as opening the taps and looking for drips. A slow seep at a joint inside a wall chase may not show for weeks under normal use, but it will show on a gauge during a properly run test. It is also not a drain test: waste pipes run unpressurised and are checked with water flow, as explained further down.

When the test must happen: before anything is covered

The only useful moment for a pressure test is after the pipes are fully joined and fixed, and before they are plastered over, screeded, waterproofed or tiled. ClickBina's renovation hold-point guide lists it as one of the checks to make before concealed piping is closed up, and ties each check to a payment stage.

If the renovation also moves fixtures, ClickBina's guide to moving a toilet, sink or shower explains why rough-in and second fix are separate stages, and the pressure test sits between them.

How a plumber should run the test

1. Finish and fix the pipework. Every joint made, every clip fixed, heat-fusion joints given time to cool.
2. Cap or plug every outlet. Each tap point, mixer point and heater point is sealed with a test plug.
3. Isolate the section. The new pipework is separated from the existing supply and any pump or tank.
4. Fill slowly and bleed the air. Trapped air compresses and makes the gauge unreliable.
5. Pump up with a test pump. A hand or electric test pump raises the pressure above normal working pressure.
6. Isolate and hold. The pump valve is closed and the gauge is left to show whether pressure holds.
7. Walk every joint. While the system is under pressure, each joint is checked by eye and by hand for damp.
8. Record the readings. Start pressure, end pressure, hold time, date and who witnessed it.

Hot and cold lines should both be tested. In many houses the hot line to each heater point is a separate run, and it is the line most likely to be forgotten because no heater is fitted yet.

Reading the gauge: pass, fail and the plastic-pipe catch

On metal pipe, a gauge that stays where it was set is a pass, and a gauge that keeps falling is a fail. Plastic pipe such as PPR behaves differently: it stretches slightly when first pressurised, so a small early drop can happen even with sound joints. A competent plumber allows for that by re-pumping after the pipe has settled and then judging the hold that follows.

Because no test pressure or hold time is published on ClickBina's guides, this page does not give one. The right figures depend on the pipe material and the manufacturer, so ask the plumber which figures they are using and why, before the test starts.

Different pipe materials, different care

PPR pipe is joined by heat fusion, and a joint that is under-heated, over-heated or misaligned can pass a quick look and still leak later. ClickBina's PPR joint guide explains how those joints fail, which is why a pressure test on new PPR is worth insisting on. Stainless and other metal pipes are joined with compression or press fittings, where a fitting that is not fully seated is the usual culprit.

Mixed systems, where new pipe joins old galvanised or old plastic pipe, need extra care at the junction. The water pipe material guide compares PPR, stainless and other options for Malaysian homes.

The second check: the water meter

After fittings are connected and the system is live, a simple cross-check is the water meter. With every tap, cistern and appliance off, the meter should not move. If it creeps, water is going somewhere. ClickBina's meter test guide shows how to read it. This does not replace the pressure test, because by then the pipes are already covered, but it catches leaks at fittings that were connected after the test.

Drain pipes are tested differently

Waste and drain pipes are not pressurised in use, so they are not pressure tested like supply pipes. They are checked by running water through every basin, shower and floor trap and watching that it drains freely and that no joint weeps. In bathrooms, the floor waterproofing gets its own ponding test before tiling, which ClickBina's bathroom waterproofing requirements guide describes.

If the test fails

A failed test is good news at this stage: the leak is found while the pipes are still visible. The plumber walks the joints under pressure to find the wet one. If none is visible, the system is split into sections and each is tested on its own until the leaking section is found. The faulty joint or fitting is cut out and remade, and the whole section is tested again from the start.

Do not accept a patch with tape or sealant on a joint that will be buried. Do not accept a second test that is shorter than the first. And do not let plastering start on the strength of a promise that the leak has been fixed: ask to see the gauge hold.

What to ask for in writing

• The pipe material and the brand of pipe and fittings used.
• The test pressure used, and the hold time.
• The pressure at the start of the hold and at the end.
• Which lines were tested: cold, hot, or both, and which outlets were capped.
• The date, and who carried out and who witnessed the test.
• A marked-up sketch of the pipe routes, so future drilling avoids them.

Keep this note with the renovation papers. If a leak appears later, it shows what was tested and when, and the route sketch saves hacking in the wrong place.

What it costs to find a leak later

A pressure test is part of doing the pipe work properly, and it is normally part of the plumbing scope rather than a separate line. What it saves is easier to price. These are ClickBina's published ranges for finding and fixing leaks after pipes are covered (indicative 2026, Klang Valley).

If a hidden leak has already soaked a bathroom floor, the redo is bigger still: the hold-point guide puts a hack, re-waterproof and re-tile at RM4,500 – RM9,000 per bathroom.

What to send on WhatsApp for a quote

• Your area and whether it is a condo, apartment or landed house.
• Which rooms are getting new pipes, and whether the whole house is being re-piped.
• The pipe material planned or already laid, if you know it.
• Where the renovation is now: hacking, rough-in, plastering or tiling.
• Whether hot-water points for heaters are included.

How ClickBina can help

ClickBina is an experienced KL & Selangor contractor for renovation, whole-house refurbishment and trade coordination, and pipe work is one of the trades a renovation has to sequence: pipes laid, tested, then covered. WhatsApp us your job details for a quote. We reply within the hour, the price we agree is a flat price with no hidden charges, and a renovation site visit is free, and a repair inspection is RM180, deducted from the bill if you go ahead.

Sources & methodology

• ClickBina renovation hold-point guide — when concealed piping is checked, and redo costs.
• ClickBina concealed pipe leak detection and burst pipe repair guides — leak detection and repair prices.
• ClickBina plumbing services guide — call-out prices.
• ClickBina PPR joint, water pipe material and meter test guides — pipe behaviour and the meter check.

How we wrote this: every RM figure is quoted unchanged from the ClickBina guides named above; they are indicative Klang Valley ranges for 2026. No test pressure or hold time is stated because none is published on those guides; get the figures for your pipe from the plumber in writing.