Storm season plumbing checklist for Gold Coast homes

The first big storm of the season is when a blocked downpipe shows itself. Water spills over the gutter, a pit in the yard bubbles up, and a puddle forms against the wall of the house. Most of the checks take an afternoon, a ladder and a garden hose.

Your place has two separate drainage systems. Stormwater carries rain from the roof and yard out to the kerb or a drain along the back of the block. The sewer carries everything from the toilets, showers and sinks. Rain is meant to stay out of the sewer entirely. A storm tests both.

The storm season plumbing checklist

1. Clear leaves and silt out of the gutters and roof valleys, and check the gutter outlets into each downpipe are open.
2. Run a hose into the top of each downpipe for a minute. The water should come out at the bottom as fast as it goes in, with nothing backing up at the joints.
3. Lift the grate on each pit in the yard and scoop out the silt, leaves and mulch sitting in the bottom.
4. Find where your stormwater leaves the property, often a small outlet in the kerb, and make sure grass, mulch or a driveway edge has not buried it.
5. Find your overflow relief gully and make sure nothing is covering it. More on this below.
6. Cut back branches hanging over the roof. Leaves in the gutter end up in the downpipes.
7. If you have a rainwater tank, check its overflow pipe is clear and runs somewhere it can drain.

If a downpipe backs up, the blockage is underground

When the hose test fills a downpipe until it overflows at a joint, and the gutter above it is clean, the blockage is in the pipe under the ground. Tree roots are one common cause. Bundaberg Regional Council lists roots entering through substandard pipes, faulty joints or loose inspection openings among the causes of blocked drains, so old joints and cracks are where to look first.

Underground blockages are not something to dig for. A plumber can run a camera through the pipe to see what is in there and exactly where, which decides whether it needs clearing or a section of pipe replaced.

The overflow relief gully: the one most people never check

Somewhere outside your house, usually near the kitchen or a bathroom, there is a small round grate sitting slightly above the ground. That is the overflow relief gully, and it is connected to your sewer, not your stormwater.

It is there for one job. If the sewer backs up, the gully overflows outside, in the garden, instead of up through your shower or toilet. That only works if the water can get out. The QBCC, which licenses plumbers in Queensland, is explicit in its guidance on overflow relief gullies that the top of the gully must not be enclosed.

• Make sure you can see it. Pavers, pot plants, garden beds and turf laid over the top are all common.
• Check the ground around it has not built up. The QBCC guidance has it sitting at least 75mm above the surrounding ground, so rain cannot run into it.
• Leave the grate loose. It is meant to lift off when the sewer pushes water up.

During the storm, take a photo

Stay off the roof. What is useful, if you can do it safely, is a photo or a short video of where the water is going: which gutter is spilling, which pit is filling, where the puddle forms. The pattern in heavy rain tells a plumber whether the problem is a gutter, a downpipe or a pipe underground, and it is gone by the time anyone arrives.

Who fixes what

The City of Gold Coast requires stormwater from a private property to drain to a lawful point of discharge, usually the kerb and channel or a drain along the back of the block. The gutters, downpipes, pits and pipes that carry water there from your house are on your side of that point. A blocked street drain or a damaged kerb is one to report to council.

The sewer is divided in a similar way, with the owner responsible for the pipes on their side of the connection. The council publishes the exact split, and it is worth checking before paying for work near the boundary.

When to call a plumber

• The same pit or downpipe overflows in every heavy rain.
• A downpipe backs up even after the gutter above it is clean.
• Water pools against the wall of the house or runs under a door.
• Drains inside gurgle or empty slowly while it is raining.
• Anything comes out of the overflow relief gully.

Any of those means a pipe needs blocked drain clearing or repair. Book it in a dry week, before the next downpour.