Quick Answer
Before purchasing an older home, inspect for leaks in the water heater, foundation leaks, basement leaks, slow or clogged drains, clogged sewer lines, sump pump problems or a leaking base of the toilets. These plumbing issues are all too frequently found in older homes (prior to the 1970s) and can easily cost thousands of dollars if they don’t show up during home inspection. The best way to prevent them from being found after closing is to have a licensed plumber’s pre-purchase inspection.
Older homes also have solid wood trim and larger lots, and older neighborhoods, but they also have plumbing systems that were designed for the quantity of water that was used in an older home. These things that worked well for a family of four in 1965, now find it difficult to work with the dishwashers, washing machines and low flow fixtures. If you’re considering a purchase in Ontario, here are 9 plumbing issues you should look out for before buying an old house.
1. Galvanized or Cast Iron Pipes
What it is: Homes built before 1960 had galvanized steel for water supply lines, and cast iron for drains and sewer lines until the 1970s. Both materials corrode from the inside.
Why it matters: The zinc coating on galvanized pipes deteriorates over time, leaving the pipes to rust and narrow over time leading to low water pressure, rusty water and ultimately pipe failure. Cast iron drain pipe causes blocked drains due to the rough, pitted interior surface that catches hair, grease and waste, which causes the problem to repeat.
How to check: On exposed pipe in the crawl space or basement. The galvanized pipe is dull gray, cast iron is thick, dark and heavy. Both will adhere to a magnet and if you don’t know, call a plumber for toilet repair or for other plumbing services that can determine materials and estimate remaining life.
2. Foundation Leak
A foundation leak will be evident by water collecting after heavy rain, white chalky residue (efflorescence) or damp basement walls. Older homes in Ontario are prone to leaking roof tiles, leaking foundation walls. An untreated foundation leak can cause mold and structural damage, and result in a massive repair expense in the future.
3. Water Heater Leaking From the Bottom
One of the most frequent water heater problems in the older houses is water leaking from the bottom of the water heater. It is typically an indicator of a failed drain valve, a corroded tank lining or sediment build-up inside the tank which creates cracks. Most tank water heaters will last 8-12 years, so request the date so the water heater was placed and ask a plumber to run a test before purchasing a home.
4. Slow Draining Sink or Tub
If it’s a slow draining sink it’s likely a clog in a single fixture. Slow drains all throughout the home indicate that there is some larger issue down the road, which is likely a sewer line clog or a sagging (bellied) portion of pipe. Inquire if the home has been inspected with a camera for the main line before.
5. Dripping Bathtub Faucet
A dripping bathtub faucet may not appear to be a big problem at first glance, but can be costing thousands of litres of water annually and is an indication of worn washers, cartridges or valve seat parts, which are typically original in older bathrooms. A simple solution at the moment, but if left untreated it can harm the tub surround and subfloor.
6. Toilet Leaking at the Base
Leaking of the toilet around the base or water leakage from the bottom of the toilet indicates that the wax ring seal is cracked or has failed, or that the toilet flange is cracked or too low. This allows water to drip out from underneath the toilet every time it uses the toilet, and slowly causes the subfloor to rot. Most of the time, a plumber who fixes toilets can re-install the toilet in less than an hour, as well as inspect the flange.
7. Clogged Basement Floor Drain
Older homes that have a cast iron floor drain can have a basement drain clogged from silt, rust, or roots. If the floor drain becomes clogged, it can cause flooding in the basement in rainy conditions, rather than preventing it. Test to see if the drain is producing clear water.
8. Sump Pump Problems
Ask about the schedule for basement pump servicing, if it has a pump in the sump pit. One of the main reasons for flooding in the basement during the spring thaw and summer storm season is due to sump pump problems, a stuck float switch, a worn motor or lack of battery back-up.
9. Sewer Line Clog or Root Intrusion
Old clay or cast iron sewer laterals are susceptible to cracking and are a source of moisture which tree roots want. When a house is sewer line clogged, its root cause is typically a clog, which presents as gurgling drains, stinking sewage water or water backing up in the lowest point in the house, typically a basement toilet or floor drain. One of the most costly plumbing-related issues to “forget” is this one, so before closing, having a camera inspection done cost doesn’t matter.
Quick Comparison: Common Old-House Plumbing Materials
| Material | Typical Install Era | Common Problem | Lifespan |
| Galvanized steel | Before 1960 | Rust, low pressure | 40–50 years |
| Cast iron | Before 1970s | Corrosion, cracking | 25–100 years |
| Lead | Before 1930 | Health hazard | Replace ASAP |
| Copper | 1960s–present | Pinhole leaks (rare) | 50+ years |
| PEX/plastic | 1990s–present | Minimal issues | 40–50 years |
Expert Tips Before You Buy
- Ask for a water leakage repair history, recurring repairs on the same wall or ceiling are a red flag.
- Request a sewer camera inspection separate from the standard home inspection; most general inspectors only glance at visible plumbing.
- Budget for pipe replacement if the home still has galvanized or cast iron supply lines this is a negotiating point, not a dealbreaker.
- Locate the main water shut-off valve during your walkthrough. If you can’t find one, that’s worth asking the seller about directly.
Why Choose BOS Plumbing and Drains
BOS Plumbing and Drains is a Canadian owned Plumbing Company that has been around for more than 20 years, and has successfully gone through all kinds of plumbing issues that are found in older homes in the GTA. They have licensed, insured plumbers that service homeowners seeking plumber mississauga, plumber oakville, and plumber brampton as well as in Hamilton, Milton, Niagara, Cambridge, Toronto, North York and Etobicoke.
They can provide a camera inspection prior to an offer, plumbers for toilet repair, leaking water heater help, or complete drain and sewer line replacement all at a fixed rate, with no costs hidden, and guarantee (and provide an upfront quote for) sewer and water line replacements for 25 years! Being a 24 hour plumber and emergency plumber service, they will be there for you 24/7 when you experience a leak or any other unforeseen plumbing issue after the move-in day for your old house.
Looking to have a plumbing inspection prior to closing on an older home? Call BOS Plumbing and Drains for a no-cost estimate and a professional opinion on plumbing and draining throughout Mississauga, Oakville, Brampton and other GTA communities.