In a nutshell
Four things cost the most to fix and are easiest to miss on a viewing: the water service from the street, the supply pipes inside, the main drain stack, and the sewer lateral under the front yard. A general home inspection touches on the first three. The lateral needs a camera, and that is usually a separate booking worth every dollar.
Working through it
1. Inspect the service pipe
Use the key-and-magnet test at the entry point to rule out lead.
2. Look along the supply lines
Rough silver pipe with threaded joints is galvanized steel. Expect low pressure and rusty water as it ages.
3. Study the stack
Cast iron that is flaking, cracked or stained at the base is near the end.
4. Camera the lateral
Ask the seller for permission and book a video inspection from the cleanout.
5. Check for flood defences
Look for a backwater valve cover in the floor and a sump pit.
Clues worth noticing
- Weak flow when two taps run together.
- A sewer odour in the basement.
- Tide marks or efflorescence on the basement walls.
- Fresh paint on one patch of basement ceiling.
Signals that it needs a licensed plumber
Book a sewer camera inspection while your offer is still conditional. The video often pays for itself in negotiation.
Calls we field, answered plainly
Will a seller allow a sewer camera?
Most will, especially if you arrange it through the agents.
Should lead be replaced before moving in?
If you can, yes, especially with young children in the house.