Why does my shower lose hot water quickly?

Your shower losing hot water quickly is typically caused by either insufficient hot water tank capacity for your household's demand, a failing water heater, or mixing valve issues. This is one of the most common plumbing complaints Toronto homeowners face, especially in older homes with original equipment.

The most likely culprit is tank size versus demand. Many Toronto homes, particularly century homes and post-war bungalows, still have 40-gallon water heaters that simply can't keep up with modern usage patterns. If multiple people shower back-to-back, run dishwashers, or do laundry simultaneously, you'll quickly exhaust your hot water supply. A typical shower uses 2-3 gallons per minute, so a 40-gallon tank provides roughly 10-15 minutes of continuous hot water under ideal conditions.

Water heater age and condition significantly impacts performance. In the GTA's hard water conditions, sediment buildup in tanks reduces effective capacity and heating efficiency. Gas water heaters typically last 8-12 years, while electric units may last 10-15 years. If your unit is approaching these ages, the heating elements (electric) or burner (gas) may be failing. You might also notice the unit taking longer to reheat between uses.

Mixing valve problems in the shower itself can cause temperature fluctuations. Toronto's older homes often have pressure-balancing valves that may need adjustment or replacement. If the hot water runs out suddenly rather than gradually cooling, this points more toward a tank capacity or heating issue rather than mixing valve problems.

Temperature setting matters too - your water heater should be set to 120°F (49°C) for optimal performance and safety. Settings below this don't provide adequate hot water volume, while higher settings waste energy and create scalding risks.

For immediate solutions, try spacing out hot water usage and checking your water heater's temperature setting. However, if the problem persists, you'll need a licensed plumber to diagnose whether it's a capacity, equipment failure, or distribution issue. Gas water heater work requires TSSA certification, and any electrical work needs ESA permits.

Next steps: Track your hot water usage patterns for a few days, then consult with a licensed plumber who can assess your current system capacity against your household's actual demand. Upgrading to a larger tank, tankless system, or high-efficiency unit might be the long-term solution, with costs ranging from $1,500-$4,000 installed in the Toronto market.