Septic System Problems When Buying or Selling a Rural Home in Ontario

A septic system is easy to ignore until something goes wrong. For a buyer, a failing or unapproved system can mean a large unexpected repair. For a seller, it can delay or derail a closing.

This article explains the Ontario rules that usually matter: permits and inspections, clearance distances, maintenance, and practical steps for each side of the sale.

Permits and inspections

Part 8 of the Building Code governs septic systems with a design flow of up to 10,000 litres per day. The local municipality usually enforces it, but in some areas a board of health or conservation authority does.

Every septic installation, repair or upgrade needs a permit and must be inspected. A permit is also needed to install, alter or repair an on-site sewage system, and permits come from the municipality's building department. Work done without a permit can be an offence under the Building Code Act, 1992.

Clearance distances that can cause problems

Older systems are sometimes too close to a well, a shoreline or a boundary. Under Part 8 of the Building Code, a septic treatment unit must be at least 15 m from a well and 15 m from a lake, river, stream, pond or reservoir. Distribution piping must be 15 m from those waters and 30 m from a well. Both must be at least 3 m from a property line.

There is an exception for cased wells. Distribution piping or leaching chambers need only 5 m from a well that has a watertight casing to a depth of at least 6 m, instead of the 30 m required for other wells.

Maintenance and the signs of trouble

Septic tanks and other treatment units must be cleaned whenever sludge and scum fill one-third of the tank's working capacity. In areas designated under source water protection (Clean Water Act), on-site sewage maintenance inspections are mandatory.

• slow drains or sewage backing up in the house
• soggy ground or odours over the system
• no records of pumping, permits or inspections
• additions or new bedrooms that were never reviewed by the building department

Buyers and sellers: who bears the cost?

No single rule decides who pays when a septic problem turns up. It depends on what the agreement of purchase and sale says, what was disclosed, and the facts of the property. A lawyer can review your contract and explain your position.

As a buyer, you can make the offer conditional on a satisfactory septic inspection and ask for permit and pumping records. As a seller, gathering your records and fixing known problems properly, with a permit and inspection, can reduce the risk of a dispute later. If the system was installed or altered without a permit, ask a lawyer about options before closing, because it may affect the sale.

What to do next

• Ask the municipality's building department for the permit history of the system.
• Confirm who enforces Part 8 in your area, since it may be the municipality, a board of health or a conservation authority.
• Arrange a septic inspection before conditions are waived.
• Check the distances from wells, water and property lines.
• Have a lawyer review any condition, repair credit or holdback before you sign.

Frequently asked questions