Tap Water Tastes or Smells Odd? Simple Checks After Plumbing Work

New tap fitted, a washing machine plumbed in, or the water just back on after a repair, and now your tea tastes of TCP or the cold tap smells like a swimming pool? It’s a common worry, and most of the time the cause is harmless and easy to track down. The Drinking Water Inspectorate (DWI) explains that the chlorine water companies use to keep drinking water safe can react with rubber and plastic parts such as appliance hoses, tap washers and kettles, giving a medicinal, plastic or “TCP” taste. A few simple checks will usually tell you whether it’s your kettle, an appliance hose, a tap, or something your water company needs to know about.

First: when not to drink it

• Don’t drink water you think may be contaminated. If it smells of petrol, diesel, heating oil, solvents or sewage, looks unusually cloudy or coloured, or the taste is strong and has appeared for the first time, use bottled water and contact your water company straight away. The DWI says a particularly bad or strong smell or taste should be reported immediately.
• Follow any notice from your water company. If Anglian Water or Essex & Suffolk Water has issued a “boil water” or “do not drink” notice for your area, follow it exactly until they lift it.
• Drink from the kitchen cold tap only. The DWI advises against drinking from the hot tap, and bathroom cold taps may be fed from a storage tank that isn’t meant for drinking water.

Quick checks to find the cause

1. Name the taste. A light chlorine or “swimming pool” taste is normal and often stronger first thing in the morning or in the early evening, Anglian Water says. A medicinal, plastic, rubbery, metallic or TCP taste points to a reaction inside the home. Write down which you notice and when it started.
2. Is it only in hot drinks? Boil some water in a clean saucepan instead of the kettle and taste it once cooled. If the saucepan water is fine, the kettle is the likely cause. Anglian Water notes that the plastic in a new kettle can cause a taste that settles after a little use; if it doesn’t, consider replacing the kettle.
3. Try another tap. Compare the kitchen cold tap with another cold mains tap. If only one tap is affected, run it for a few minutes and taste again: new or worn tap washers can cause the taste, and flushing sometimes clears it.
4. Check plumbed-in appliances. Switch the washing machine or dishwasher off first. Then turn off its small service valve (usually a quarter turn of the lever or slot, so it sits across the pipe) and run the kitchen cold tap for a while. If the taste goes, the appliance hose is the likely culprit. Don’t force a stiff valve, and only do this if the area is dry. Remember to turn the valve back on before you next use the appliance.
5. Ask your neighbours. If neighbours notice the same taste or smell, the problem is probably in the mains rather than your pipes, so report it to your water company. Anglian Water’s customer line is 03457 145 145.
6. Note what you found. The DWI suggests telling your water company what the taste or smell is like, which taps are affected, whether neighbours have it too, and when it started. It also helps your plumber.

Fixes that usually sort it

• Chlorine taste you don’t like: keep a covered jug of tap water in the fridge for a few hours. Anglian Water and Water UK both say to use it within 24 hours, because once the chlorine has gone the water is no longer protected against bacteria.
• Appliance hose: the fix is an approved single check valve (a non-return valve) where the hose joins the pipework, or a replacement approved hose. This stops water sitting in the hose from being drawn back into your drinking water. Water UK and the DWI both say these connections should have one. We’re happy to fit it for you.
• Tap washers: Anglian Water suggests replacing a problem tap or washer with one approved by WRAS (the Water Regulations Advisory Scheme). If every tap tastes odd, the washer in the stopcock may be the cause, which is a job for a plumber.
• Garden hose: WaterSafe notes a hose left permanently on an outside tap can cause the same taste. Take it off when you’re not using it; a plumber can fit a double check valve on the outside tap.

What not to do

• Don’t fit cheap unapproved hoses, valves or taps. Anything connected to your drinking water must meet the Water Supply (Water Fittings) Regulations 1999, and the wrong fitting can cause both tastes and leaks.
• Don’t add home-made filters or chemicals to the supply, or disconnect pipework you’re unsure about.
• Don’t touch the outside or boundary stop tap. It’s usually owned by the water company, may need a special key and can serve neighbours too, so don’t dig it up or force it.
• Don’t use the hot tap or a bathroom tap for drinking while you’re testing.

When to stop and call us

• The taste started after plumbing work and flushing the tap hasn’t cleared it.
• An appliance hose is the cause and you’d like a check valve or approved hose fitted properly.
• A service valve or tap is stiff, leaking or won’t turn. Don’t force it. Our washing machine and dishwasher leak guides explain what to do first.
• Every tap tastes odd and your neighbours’ water is fine, which may mean a stopcock washer or a fitting inside your home.
• You’d like new WRAS-approved taps fitted. If limescale is also a problem, see our limescale guide.

Our plumbing engineers handle taps, valves, appliance connections and stopcocks, and our emergency plumbing team can help day or night if a fitting starts leaking.

If a leak starts

If a valve or hose starts leaking, turn off the inside stopcock first. Here’s how to find and turn off your stopcock; don’t force it if it’s stiff. The outside or boundary stop tap is usually the water company’s (Anglian Water or Essex & Suffolk Water) and may need a special key, so contact them about a leak on their side and check whether neighbours are affected (more in our outside stop tap guide). Keep water away from sockets and appliances. A tripped RCD or MCB may be reset once from a dry spot with dry hands; if it trips again, leave it off and call a registered (Part P) electrician. Never touch electrics near water.

Smell gas or suspect carbon monoxide? Leave the property, open doors and windows if it’s safe, don’t use light switches or naked flames, turn the gas off at the meter only if it’s safe to do so, and call the National Gas Emergency Service on 0800 111 999. Get medical advice if anyone has CO symptoms such as headaches, dizziness or nausea. Only a Gas Safe registered engineer may work on gas appliances; you can check an engineer on the Gas Safe Register.

Sources and further reading

• Drinking Water Inspectorate: taste and odour in drinking water
• Drinking Water Inspectorate: TCP or medicinal taste and odour
• Anglian Water: water that tastes bitter, metallic or of disinfectant (PDF)
• Anglian Water: water that tastes or smells of chlorine (PDF)
• WaterSafe: rubber, plastic or TCP tastes
• Water UK: looking after water in your home (PDF)

This is general safety guidance. If you’re unsure, stop and call a qualified engineer.