Melbourne Storm Season Plumbing Checklist: 19 Jobs Before the Rain

Melbourne storms do not arrive politely. A warm northerly afternoon turns into a south-westerly change, the sky goes green over the bay, and in forty minutes a suburb gets the rain it would normally see in a month. Flinders Street floods, the laneways of Fitzroy and Collingwood run like creeks, and a few hours later the plumbing problems begin: sewers backing up through floor wastes, downpipes overflowing into eaves, and outdoor hot water units that quietly die a day or two later.

Almost all of it is predictable. Most of it is preventable with an hour’s work in spring. This is the checklist we would do on our own homes — and at the bottom of the page it is tickable, so you can work through it and come back to it next year.

Why Melbourne storms are a plumbing problem

Three things make Melbourne different from a city with steady rain.

The rain comes in short, violent bursts. A thunderstorm cell can deliver 30 to 50 millimetres in under an hour. Gutters, downpipes and stormwater pits that cope with a normal day are overwhelmed in minutes, and the overflow goes wherever gravity sends it — usually into the eaves, down the wall cavity, or across the yard to the lowest point, which is often the overflow relief gully of the sewer.

The drainage network is old where the houses are old. The inner north and the inner west still run on clay sewer branches laid between the 1880s and the 1930s. Clay pipes crack, joints open, and plane-tree roots find every gap. Each crack is a doorway for stormwater into the sewer. Melbourne Water manages the main drains and the rivers; the pipes under your own block are yours, and they are the ones that let the water in.

The ground moves. West of the Maribyrnong, the basalt-plain clay swells when it gets wet and shrinks when it dries. A buried pipe that was straight in February can be cracked by May. That is why the same Footscray and Maribyrnong streets block every autumn.

Add the bayside strip, where low-lying streets in Elwood and Port Melbourne flood from the outside in when a storm surge meets high tide, and you have a city where the first big cell of the season reliably produces a wave of emergency calls.

Before the season: the 60-minute checklist

Do this in September or early October. The Bureau of Meteorology issues severe thunderstorm warnings only hours ahead, which is not enough time to clean a gutter.

1. Clear the gutters. Leaves, plane-tree seed balls and silt. From a ladder, never from the roof. Two-storey or slate roof: pay someone.
2. Run a hose down every downpipe. Water should come out freely at the bottom, into the stormwater pit or onto the ground. If it backs up, the downpipe or the underground stormwater line is blocked.
3. Lift every surface grate and stormwater pit lid and clear it. Pour a bucket of water down each one to check it drains.
4. Find the overflow relief gully. It is the grated drain just outside the laundry or kitchen wall, and it is the one safety valve your sewer has: when the sewer backs up, it is supposed to overflow there, outside, instead of through your shower drain inside. Pot plants, mulch and paving sitting on it defeat the whole point. Clear it and keep it clear.
5. Test the sump pump if the garage or basement has one. Pour in 20 litres. It should start by itself and clear within a minute.
6. Check the casing of an outdoor hot water unit. No rust holes, no cracked or missing seals, especially on top where the rain lands. A unit that gets water into its controls fails a day or two after the storm.
7. Check the seals on outdoor power points near the hot water unit and the pump.
8. Close and reopen the stop tap at the water meter. A valve that is moved once a year still moves in an emergency. One that has not been touched for a decade may not.
9. Test the floor wastes in the laundry, garage and basement with 20 litres each.
10. Photograph everything — gutters, downpipes, drains, taps and the hot water unit. If you ever need to claim, the before photos are gold.

When a severe thunderstorm warning is issued

Melbourne cells often give only a few hours of notice.

• Move furniture, tools and bins away from downpipe outlets and drains.
• Move cars off the lawn and out of low-lying laneways. Wet ground gives way and can crush pipes underneath; laneways flood first.
• Move soft furnishings away from windows that face the wind.
• Keep the emergency numbers where you can see them: your insurer, your plumber, the SES on 132 500 and your water company’s faults line (it is on the bill).
• If your home has backed up before, avoid showers, the washing machine and the dishwasher at the peak of the rain. Every litre you send down comes back up.

After the storm

• Walk the property in the next day or two. New water marks near the ceiling point to the roof or gutters; a boggy patch of lawn points to a pipe below.
• Test the hot water. Outdoor units can fail a day or two after a storm, when water that got into the controls does its work.
• Check inside walls for new or growing damp patches.
• If something was damaged, gather photos, invoices and notes for the insurer and lodge the claim as soon as you can.

The storm problems that fill the phone

Sewer backing up through the floor waste. The classic Melbourne storm call. Stormwater has entered the sewer and the branch cannot cope. If the inspection shaft is full and overflowing while nobody is using water, the blockage is in the water company’s main — ring their faults line and they clear it free. If it only overflows when you run water, it is in your pipes, and a licensed plumber clears it, usually with an electric eel or a jet.

Downpipe overflowing at the top. Almost always a blocked underground stormwater line, not the gutter. Water has nowhere to go and climbs back up.

Dead hot water two days later. Rain through a cracked casing or a perished seal. Sometimes a dry-out and a new igniter; sometimes a new unit.

Water coming through the ceiling. Gutters overflowing backwards into the eaves. A gutter problem, but a plumber’s job to make safe if the ceiling is sagging.

When to call, and what it costs

A sewer coming up inside the house, water through the ceiling or a flooded floor is an emergency at any hour, and with us the hour does not change the rate — $130-170 an hour, no call-out fee. A slow drain or a gutter that overflowed once can wait for a daytime booking, and we will say so. If you are not sure which side of the line you are on, our guide to what counts as an emergency sorts it out, and the blocked drain page explains how a storm blockage is cleared and priced.

Tick through the checklist below. It is saved on your device, so you can come back to it before the next cell rolls over the bay.