Is Your Shower Running Cold? Here’s What to Check (Before You Call Someone Out)

There’s nothing worse than stepping into the shower expecting a blast of warmth… and getting hit with freezing water instead. It’s one of the most common reasons people in Exeter and the surrounding areas call us at EPM — and nine times out of ten, they ask:

“Why is my shower suddenly running cold?”

So here’s what we tell them. In this guide, we’ll walk you through the most common causes of cold showers — what you can check yourself, when to call in a pro, and how to avoid it happening again.

1. Is Your Boiler Working?

It might sound obvious — but you’d be surprised how often the issue starts with the boiler.

Is the boiler showing an error code?
Is the pressure too low? (It should usually sit between 1.0–1.5 bar)
Has the pilot light gone out?
Has there been a power cut or fuse trip?

If your radiators are hot but your shower’s cold, this could still be the boiler — especially with combi boilers that prioritise central heating over hot water if there’s a fault.

Is It an Electric Shower?

If you’ve got an electric shower (one that heats water independently of your boiler), here’s what to check:

Is there power to the shower unit?
Check the isolator switch (often just outside the bathroom) and the fuse board.
Is the shower heating element faulty?
If the unit turns on but doesn’t heat, the internal element may have failed — and these aren’t user-replaceable.
How old is the unit?
Electric showers usually last 6–10 years. Older units can start losing heating power or cutting out altogether.

3. Mixer Showers: Are You Getting the Right Water Flow?

Mixer showers blend hot and cold water from your system. If something is disrupting the balance, you’ll feel it instantly — either with cold water only, or sudden temperature changes.

Has someone flushed a toilet or turned on a tap?
This can drop pressure in one supply line and cause imbalance.
Are there limescale or debris blockages?
Even in soft water areas like Exeter, sediment or old pipework can clog shower cartridges.
Do you have a faulty thermostatic cartridge?
These control the temperature mix. When they fail, it often results in a cold or lukewarm shower, even if everything else seems fine.

We’ve been to plenty of jobs where the shower cartridge was faulty — and sometimes it’s cheaper and easier to replace the entire shower, especially when the make or model is unknown, or parts are no longer available.

4. Believe It or Not — Rodents Sometimes Chew Pipes

Yep, we’ve seen it. Especially in older or rural properties, mice have been known to chew through plastic pipework in lofts or behind stud walls. It’s rare — but when it happens, it can reduce flow to showers or cause leaks in hot water feeds.

If you’ve noticed drops in water pressure or unusual damp spots, it’s worth investigating.

5. Does It Happen All the Time — or Just Sometimes?

This helps narrow things down. If your shower only runs cold:

At certain times of day
When multiple people are using water
During colder months

…then it might be a capacity issue, not a fault. Your system might need upgrading — or just rebalancing — to meet demand.

When to Call in a Professional

You can check a lot of the basics yourself. But when the problem isn’t obvious — or you’re unsure about anything involving electrics, boilers or pipework — it’s always safest to get a qualified engineer involved.

At EPM, we’re trained to deal with all types of hot water systems, from combis to cylinders to electric showers. We won’t just swap parts for the sake of it — we’ll pinpoint the issue properly, and explain your options clearly.

Planning a Bathroom Refurb?

If your shower is old or your hot water system has been struggling for a while, it might be time to consider a full refresh. We can help design, install and future-proof your bathroom — whether you’re upgrading one shower or redoing the whole room.