Why Is My Water Pressure Suddenly Low? Common Causes in Older Calgary Homes

If you are asking why your water pressure is suddenly low, the cause usually comes down to one of a few things: a buildup of mineral scale in older pipes, a hidden leak, a failing pressure regulator, a partially closed valve, or a municipal supply issue. In older Calgary homes, mineral scale from the city’s hard water and aging galvanized pipes are among the most common culprits.

If your water pressure has dropped and the cause is not obvious, a licensed Calgary plumber can diagnose it properly. R N T Plumbing and Heating provides upfront pricing, a free plumbing inspection with every service, and a 5-year warranty on all parts and labour.

If the drop is sudden and affects the whole house, the cause is different from a slow decline at a single faucet. The sections below help you narrow it down.

Is It One Fixture or the Whole House?

The first thing to determine is whether the low pressure affects a single tap or every fixture in the home. This single question narrows the cause dramatically.

If it is one fixture, the problem is local. A clogged aerator, a blocked faucet cartridge, or a partially closed supply valve under that fixture is the likely cause. This is usually a minor fix.

If it is the whole house, the cause is somewhere in your main supply, your pressure regulator, or the municipal supply. These causes range from simple to serious.

Common Causes in Older Homes

Mineral Scale in Aging Pipes

Calgary has notably hard water, meaning it carries a high concentration of dissolved minerals. Over years and decades, those minerals deposit on the inside walls of pipes as scale. In older homes with original galvanized steel pipes, this scale narrows the interior diameter of the pipe, restricting flow and reducing pressure throughout the home. This is one of the most common reasons older homes experience gradually worsening pressure.

A Hidden Water Leak

A leak somewhere in your plumbing system diverts water away from your fixtures, lowering pressure. A sudden pressure drop combined with the sound of running water, damp spots, or an unexplained increase in your water bill points strongly toward a leak. This warrants prompt attention because a hidden leak causes damage the longer it goes unaddressed.

A Failing Pressure Regulator

Many homes have a pressure regulator, also called a pressure reducing valve, where the main line enters the home. This device keeps incoming municipal pressure at a safe level for your home’s plumbing. When a regulator begins to fail, it can cause a sudden and noticeable drop in pressure across the whole house. A failing regulator needs to be replaced by a plumber.

A Partially Closed Valve

If you or someone else recently did work on the plumbing, a main shut-off valve or the valve at the water meter may not be fully open. This is worth checking before assuming a more serious cause. Make sure your main shut-off valve is turned fully to the open position.

Corroded Galvanized Pipes

Homes built before the 1960s often have galvanized steel supply pipes. These corrode from the inside over time, and the corrosion combined with mineral scale progressively restricts flow. If your older home still has its original galvanized plumbing, this is a very common cause of declining pressure and often signals that the pipes are nearing the end of their usable life.

Could It Be the City Supply?

Sometimes low pressure has nothing to do with your home at all. A water main break, scheduled maintenance, or work on the municipal system can temporarily reduce pressure. A quick way to check is to ask a neighbour whether they are experiencing the same issue. If the whole street is affected, the cause is on the City side. You can contact the City of Calgary at 311 to confirm whether there is known work in your area.

When to Call a Plumber

Some pressure issues are simple to resolve yourself, such as cleaning a clogged aerator or fully opening a valve. Others require professional diagnosis. Call a plumber if:

• The low pressure affects the whole house and is not a municipal issue
• You suspect a hidden leak
• Your home has older galvanized pipes
• You notice the pressure dropping progressively over time
• Cleaning aerators and checking valves makes no difference

A licensed plumber can pinpoint the cause, whether it is scale buildup, a failing regulator, a leak, or aging pipes, and recommend the right solution.

Get to the Bottom of Your Low Pressure

Call (825) 883-9264 or book online.