Some of the biggest water losses happen inside the home where you rarely look. From toilets to filters, here are the most common indoor water wasters we see in Ontario homes, along with the signs that something may be quietly draining your system if you are on a cistern or well.
Toilets That Don’t Fully Shut Off
A toilet that runs long after flushing is one of the most common hidden indoor water losses. Even a small internal leak can waste hundreds of litres a day without making much noise.
Signs to watch for:
- “Ghost refills” long after flushing
- Small ripples on the bowl surface
- A faint hiss coming from inside the tank
If you notice any of these, a part inside the tank may not be sealing properly. A plumber can diagnose this quickly and prevent unnecessary water loss.
Slow Leaks in Pump Rooms or Crawlspaces
Many homes hide pumps, pressure tanks, and lines behind walls or in crawlspaces.
Common trouble spots:
- Around the pump housing
- Fittings on the pressure tank
- Joints near heat tape
- Shutoff valves that aren’t fully sealing
If your pump cycles when nobody is using water, or you spot damp areas near equipment, a slow leak may be happening in the background.

Water Softeners Using More Water Than Expected
Water softeners can use large amounts of water, especially if they regenerate too often or get stuck partway through a cycle.
Signs something is off:
• The softener sounds louder than usual
• Your cistern drops faster than normal
• Salt levels disappear quicker than expected
If you see any of these signs, it often means the softener is working harder than it should. A quick check from a water system professional can confirm whether it’s running properly and help prevent unnecessary water loss.
Furnace Humidifiers That Run Constantly
Many homes have bypass humidifiers attached to the furnace. When a part sticks open, water can run straight to a drain line without any obvious sign.
Watch for:
• Constant dripping from the drain tube
• Mineral buildup around the humidifier
• Higher winter water use with no clear cause
These systems can quietly waste a significant amount of water until someone spots the issue.
Filters or UV Systems That Are Overdue
Clogged filters reduce water pressure, causing appliances and fixtures to run longer. That leads to more water used for less performance.
Signs your system might need fresh filters:
• Slow taps
• Appliances taking longer to fill
• Pressure dropping on the gauge
Staying on schedule with filter and UV bulb replacement keeps your entire system running more efficiently.

Older Appliances That Use More Water Than You Think
Older dishwashers and washing machines can use double or triple the water of newer models.
Typical use per load:
• Older dishwasher: 35–60 L
• Modern dishwasher: 10–20 L
• Older top-load washer: 70–110 L
• High-efficiency front-load: 35–70 L
If you notice dips in water levels after laundry days, appliances may be part of the reason.
Staying Ahead of Indoor Water Loss
- Listen for pump cycling at odd times
- Check your cistern level weekly
- Keep track of appliance behaviour
- Stay up to date on filter changes
- Install water-level monitoring (if you haven’t already)
A few simple checks help prevent surprises and stretch the time between deliveries.