Why is there a manhole in my backyard?

A round concrete or metal lid in the backyard, often in the lawn or a garden bed, is usually a sewer maintenance hole (the old name is manhole). It gives Sydney Water access to the sewer main that runs through your property. It's very common on older blocks in the Eastern Suburbs, where sewer mains were laid through back and side yards rather than under the street. Here's what it means for you.

What it is

The rules

• Keep it accessible: don't cover it with soil, pavers, decking or garden beds. Sydney Water needs to be able to get to it.
• Don't raise or lower it yourself: if you're changing levels around it, its height may need adjusting by an approved contractor.
• Building near it: structures over or near Sydney Water's sewer mains and maintenance holes need approval. Check before you plan a pool, shed, extension or driveway nearby.
• Don't open it: sewers contain dangerous gases. Leave it to Sydney Water.

When sewage comes out of it

If sewage is overflowing from the maintenance hole, the blockage is in Sydney Water's main, not your pipe. Report it to Sydney Water. If your own drains are blocked but the maintenance hole is fine, the problem is usually in your private line, and that's where we come in. Our sewer responsibility guide explains who looks after what.

In southern Eastern Suburbs homes

Many older blocks in Matraville, Maroubra, Malabar and Botany have the sewer main running through the backyard, with a maintenance hole somewhere along it. We often find them buried under lawn or garden beds. Knowing where it is helps when planning work and makes it easy for Sydney Water if their main blocks.

Related help: sewer responsibility guide, blocked drains, where does sewage go?, sewer vent pipes and CCTV drain inspection. Local pages: Matraville, Maroubra, Malabar and Botany. Browse all our plumbing guides.