A Local Plumber's Guide to Stormwater & Flooding

Living around the Lake is a dream, but when the East Coast Lows roll in, our backyards can quickly turn into extensions of Lake Mac itself. As a local plumber, I’ve spent countless rainy days wading through sodden Speers Point gardens and unblocking drains in Belmont.

Heavy rainfall doesn’t have to be a disaster. Most of the flooding issues I see come down to a few common "pitfalls" that are often easily fixed with the right drainage setup. Here is what every Lake Macquarie resident needs to know about managing water on their property.

The Gutter "Fall": Why Gravity is Your Best Friend

The most common mistake I see isn’t a lack of gutters, but gutters that aren't actually working. For water to move, your gutters need the correct fall (slope).

• The Rule of Thumb: In NSW, eaves gutters should have a minimum fall of 1:500. This means for every 5 metres of gutter, there should be at least a 10mm drop toward the downpipe.
• The Pitfall: Over time, brackets can sag or "back-fall" due to heavy debris or rusted spikes. If you see water pooling in your gutters long after the rain stops, or splashing over the side during a storm, your fall is likely out of whack.

The Fix: Re-pitching gutters isn't a DIY job for the faint of heart, but ensuring your downpipes aren't "choked" with leaf litter from our local gums is a great start.

Stormwater Pits: The "Catch-All" Solution

If you have a low spot in your yard where water naturally pools, common in the clay-heavy soils of suburbs like Cardiff or Glendale, you need a Stormwater Pit.

• How they work: These are typically plastic boxes buried in the ground with a grate on top. They act as a collection point for surface water.
• The Fix: We install these at the lowest point of your lawn or driveway. Once the water enters the pit, it's piped away to the street or a legal discharge point.

Pro Tip: Always keep the grates clear of mulch and grass clippings. A pit is only as good as the water that can get into it!

Ag Pipe: Solving the "Soggy Lawn" Syndrome

Ever stepped onto your grass two days after rain and heard a squelch? That’s sub-surface water with nowhere to go. This is where Agricultural Pipe (Ag Pipe) comes in.

• The Science: Ag pipe is perforated (full of tiny holes). It’s designed to be buried in a trench filled with 10–20mm "blue metal" or gravel and wrapped in a "sock" (geotextile fabric).
• The Pitfall: Many people bury ag pipe directly in the dirt. Without the gravel and fabric, the tiny holes clog with silt in months, rendering the pipe useless.
• The Fix: A correctly installed French drain (Ag pipe + gravel + fabric) acts like a magnet for groundwater, pulling it out of the soil and carrying it away before it can reach your home’s foundations.

Downpipes: Are You Overloading the System?

In Lake Macquarie, we often see older homes with only one or two downpipes for a massive roof area.

• The Requirement: Under the National Construction Code, one downpipe shouldn't serve more than 12 metres of gutter length.

The Fix: If your gutters are overflowing even when clean, you likely need an additional downpipe. Increasing the size from a standard 90mm round to a high-capacity rectangular downpipe can also make a world of difference during those 20-minute summer downpours.

A Note on Council Regulations

In Lake Macquarie, you are legally required to accept "natural" overland flow from your neighbours, but you cannot redirect your own stormwater so that it concentratedly pours onto their property. All "collected" water (from roofs and pits) must be piped to the street curb or a designated council easement.



Is your backyard still a swamp after the latest storm? I can come out and inspect your lines to see if tree roots are the culprit or check your lawn and garden layout to help determine if we need to design a better drainage plan.