Plumbing red flags in an inspection

Plumbing problems are among the most common findings in a home inspection, and some of the most costly if missed. The biggest red flags are pipe materials with a history of failure, active or past leaks, an old or poorly installed water heater, slow or backing-up drains, and signs of trouble in the sewer line. Most can be confirmed and priced by a licensed plumber before you commit.

Pipe materials to watch for

The type of supply and drain piping tells you a lot about what to expect. Some materials are known to cause problems as they age.

Copper, PEX and modern plastic drain pipe are generally reliable when properly installed, though installation quality still matters.

Red flags during the inspection

It helps to picture a house's plumbing as two systems that meet at the fixtures: pressurized supply bringing clean water in, and gravity drainage with venting taking waste out. Each part has its own typical problems.

Leaks and water damage

• Stains on ceilings below bathrooms and kitchens.
• Soft or stained flooring around toilets, tubs and showers.
• Corrosion, green or white deposits on fittings and valves.
• Drips or moisture under sinks and behind appliances.
• Musty smells or mould in cabinets or basements. See moisture, mould and indoor air.

Water pressure and flow

• Low pressure when two fixtures run at once, which may point to corroded supply pipes.
• Very high pressure, which strains fixtures and connectors; a pressure-reducing valve may be needed.
• Discoloured water when taps are first opened.

Drains and venting

• Slow drains in several fixtures, which can point to a problem in the main line rather than a single clog.
• Gurgling sounds or sewer smells, which can mean poor venting or dry traps.
• Missing or improper traps, such as S-traps under sinks.
• Signs of past backups at floor drains.

Water heater

• Age near or past the typical service life for its type; the manufacture date is usually on the label.
• Rust or water at the base of the tank.
• A temperature and pressure relief valve without a proper discharge pipe extending toward the floor.
• Venting problems on gas units, such as poorly sloped or disconnected vent pipes, or scorch marks near the burner.
• No seismic strapping where it is required, such as in parts of BC.

The sewer line

The main sewer line from the house to the city connection is out of sight but can be one of the most expensive repairs. In older homes, homes with large trees nearby, or homes with a history of backups, consider a camera inspection of the sewer line by a plumber. It can show roots, cracks, sags (bellies) and offset joints. A backwater valve helps protect against sewer backups; check whether one is present and working. See why basements leak for more on backups.

A typical case: one stain, several questions

During a pre-purchase inspection of a 1960s bungalow, the inspector finds a brown stain on the basement ceiling below the main bathroom, a toilet that rocks slightly on its base, and galvanized supply pipe visible at the main shut-off with copper elsewhere. Each finding raises a question the buyer should get answered before firming up:

1. Is the stain active? The inspector takes a moisture reading at the stain and runs the tub and flushes the toilet above. A dry reading after use suggests an old leak; a damp one means it is ongoing.
2. Is the toilet seal failing? A rocking toilet can break the wax seal and leak onto the subfloor every time it is flushed. Soft flooring around the base suggests damage to the floor structure, which costs more than resetting the toilet.
3. How much galvanized pipe is left? Copper in the visible areas does not mean the whole house was repiped. The plumber's quote should say whether hidden sections, such as inside walls or the line from the street, are still galvanized.
4. What about the sewer line? A house of this age with mature trees in the yard is a good candidate for a sewer camera inspection before the conditions expire.

Questions to ask the seller

• Has the house had any leaks, floods or sewer backups, and what was done?
• When was the water heater installed, and has it been serviced?
• Has the house been repiped, and with what material?
• Is there a backwater valve, and when was it last checked?
• Have there been any insurance claims for water damage?
• Are there any receipts or warranties for plumbing work?

What to do with the findings

1. Ask the inspector which findings are urgent, which need further evaluation and which are routine maintenance.
2. Have a licensed plumber evaluate significant items and provide a quote before your conditions expire.
3. Check with your insurer about any pipe materials that may affect coverage.
4. Find out whether your municipality has programs for lead service line replacement or backwater valve installation.

Our guide on how to read a home inspection report helps sort findings into what matters now and what can wait.

How ehZee can help

An ehZee home inspection looks at visible supply and drain piping, fixtures, the water heater and signs of leaks. You can walk through with the inspector, ask questions on the spot and hear the findings on the day, with a written report within two days.

Common questions