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Can the trench go there? Check the setbacks

Bore, dam, waterway, boundary, building, pool, stormwater drain — the distances your council will measure.

Setbacks are the first thing a council checks and the last thing a homeowner thinks about. They are not bureaucracy: they are the distance effluent travels through soil before it reaches something that matters.

The values below follow WaterNSW's requirements for domestic systems, which are among the stricter published sets. Victoria, Camden Council and Queensland councils all publish different numbers — sometimes gentler, sometimes far harsher. Enter your real distances, then check your own council before you dig.

Check

Distance to a bore or well (m)

The most important distance on the block: it protects the water you drink. — min 100 m (WaterNSW, domestic).

Distance to a waterway (from high water level) (m)

Creeks, rivers and permanent watercourses. — min 100 m (WaterNSW / Camden).

Distance to a dam (from high water level) (m)

Victoria demands up to 300 m if the dam is potable. — min 40 m (WaterNSW).

Distance to a stormwater drain (m)

A drain is a direct pipe to a waterway. Victoria: 50 m open, 6 m closed. — min 40 m (WaterNSW / Camden).

Distance to the property boundary, up-slope (m)

Down-slope the requirement drops to about 3 m. Camden Council wants 12 m up-slope. — min 6 m (WaterNSW).

Distance to a building, up-slope (m)

Down-slope, WaterNSW allows 2 m. Victoria and Camden say 3 m. — min 6 m (WaterNSW).

Distance to an in-ground pool or water tank (m)

WaterNSW requires the trench to be 15 m away and down-slope of it. — min 15 m (WaterNSW, primary effluent).

Where the jurisdictions disagree, they disagree loudly. A bore is 100 m away under WaterNSW, 250 m under Camden Council, 50 m in Victoria on Category 1/2a soils and 20 m on Categories 2b–6. A dam is 40 m for WaterNSW and up to 300 m in Victoria if it is potable.

Two rules trip people up. Slope matters: boundaries and buildings need 6 m up-slope but only 2–3 m down-slope, because effluent runs downhill. And WaterNSW specifically requires trenches carrying primary effluent to sit 15 m from and down-slope of in-ground pools and water tanks.

If a distance fails, the answer is usually to move the land application area rather than the tank. And remember the reserve area: AS/NZS 1547 expects a 100% duplicate area, kept clear of traffic and buildings, ready to take over.

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