Draining the water lines in your home is one of those jobs that sounds drastic but is actually straightforward, and there are several good reasons to do it. You might be preparing for a plumbing repair, trying to silence banging pipes, or shutting a property down before an extended trip away. Whatever the reason, doing it in the right order matters, because doing it in the wrong order can damage your hot water system or leave water trapped exactly where you do not want it. Here is the process our team follows, adapted for the average Perth home.
Know why you are draining first
The reason shapes the method. If you are fixing water hammer, you only need to empty the lines and refill them, because the goal is to restore the air cushions that absorb pressure shocks. If a repair is planned, you need the section you are working on empty and depressurised. If you are leaving the property vacant for months, you want as little standing water in the system as possible, both to limit damage if a fitting fails and to avoid stagnant water sitting in the lines. Perth homes do not face the frozen pipe risk common overseas, so full winter draining is rarely necessary here, but vacancy draining is genuinely worthwhile.
Step one, shut off the mains
Find your main water shut off valve. In most Perth properties it sits near the water meter at the front boundary, and many homes have a second isolation valve where the supply enters the building. Turn it clockwise until it stops. If the valve is stiff, seized or weeping when you touch it, stop there. A seized mains valve is a problem worth fixing on its own, because it is your only line of defence in a burst pipe emergency.
Step two, open the highest taps
Air has to enter the system for water to leave it. Start at the highest fixtures in the house, which in a two storey home means the upstairs basin and shower, and open both hot and cold taps fully. In a single storey home, start with the taps furthest from the meter. You will hear air being drawn in as the water begins to fall through the pipes.
Step three, work down to the lowest points
Now open every remaining tap in the house, working your way toward the lowest outlets. The lowest tap on the property, often a garden tap or a laundry trough, is where most of the water will exit, so let it run until it slows to a trickle and stops. Flush every toilet to empty the cisterns. If you want the bowls empty too, the remaining water can be pushed out with a quick plunge or removed with a sponge.
Step four, treat the hot water system with care
This is where people get into trouble. Storage hot water systems hold a large volume of heated water under pressure, and they must never be left switched on while empty, because heating elements burn out within minutes without water around them. Switch off the power at the breaker, or turn the gas control to off, before you drain anything. For a standard shutdown you do not need to empty the tank itself, only the lines, so closing the cold inlet valve on the unit is enough. If the tank must be fully drained for a repair or long vacancy, that involves the drain cock and the temperature and pressure relief valve, and we recommend having a licensed plumber handle it.
Refilling the system
Refilling is the reverse. Close every tap except the lowest one, open the mains slowly, and let each fixture run until the sputtering stops and the flow is smooth, working from lowest to highest. Air in the lines is noisy but harmless and clears within a minute or two of running. Only once water flows cleanly from the hot taps should the hot water system be switched back on. Expect a small amount of discolouration on first refill as sediment stirs up, which should clear quickly.
When draining reveals a bigger problem
Draining and refilling a system has a way of exposing weaknesses. Valves that will not close, taps that will not reopen cleanly, persistent discolouration or a hot water system that relights with a struggle are all signs of components at the end of their life. Our team has spent more than 25 years inside Perth plumbing systems, and we would far rather help you deal with a tired valve today than a burst fitting during your holiday. If anything in this process does not go to plan, give Drains Plus a call and we will get it sorted.
For water hammer specifically, the drain and refill process works because older pipe systems rely on air chambers, short vertical sections of pipe near fixtures that hold a cushion of trapped air. Over months of use that air gradually dissolves into the water, the cushion disappears and each fast closing tap or appliance valve sends a shockwave banging through the pipes. Draining the system completely allows air back into those chambers, and refilling from the bottom up traps it where it belongs. If the banging returns within a few weeks, your system either lacks proper arrestors or has a pressure problem, and both are worth a professional look rather than repeated draining.
Two small preparations make the whole job smoother. First, warn the household, because a family member unknowingly turning on a tap or starting the dishwasher mid process can pull sediment through the system. Second, if you are draining before an extended absence, take the extra step of turning off the supply valves to the washing machine and dishwasher and leaving internal doors and the dishwasher door ajar. Trapped humidity in a sealed empty house is how you come home to mould, and it costs nothing to prevent.
