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Which? Trusted traders tips on five common plumbing problems

Our Which? Trusted traders share their top tips on how to take preventative action to avoid spending a fortune on common plumbing and boiler issues.

In this article

1. No hot water due to immersion heater failure

An immersion heater doesn’t require a tank in the loft, and instead heats water directly from the mains in a cylinder. This allows for a greater supply of hot water at any one time, so immersion heaters are usually found in larger properties with several occupants.

But what happens when the hot water goes cold?

How to solve the problem

According to Which? Trusted trader Danny Morris from MJC plumbing, problems are often due to a build-up of limescale in the immersion heater. This means the immersion heater will need to be replaced. Danny explains that to do this, ‘the cylinder needs to be drained, refilled and vented’.

Most plumbers will charge by the hour for this work. Hourly rates will vary around the country, and you may need to account for travel and parking charges, too. Danny is based in London and charges £85 an hour. He estimates this job would take between one and three hours. The larger the cylinder, the longer it will take.

Prevention and cost-saving tips

Danny recommends fitting a limescale preventer – particularly in hard-water areas. This is a straightforward job; once the cylinder is drained it should be less than an hour’s work. A limescale preventer costs £30-£40, plus the labour charge.

While the cylinder is drained, Danny recommends fitting a new drain cock as well. They are cheap to buy – costing around £3 or less. ‘Any decent plumber will do this as a matter of course,’ he said, ‘but it’s worth checking.’ Renewing the drain cock makes it easier to drain the system in the event of a problem. Danny explains: ‘It’s common for drain cocks to scale up, which increases the time and cost of draining the system.’

Prevention is always better than cure – see our 10 expert tips on how to look after your plumbing system.

2. Clear a blocked sink

Your sink is blocked. You can’t clear it yourself, you don’t know what’s causing the blockage, and you need to call in the plumber to clear it.

Which? Trusted Traders has endorsed plumbers in your local area.

How to solve the problem

Danny said: ‘It’s an unpleasant job – it means sticking a rod down the drain to clear the blockage. If access is tricky, it may be necessary to dismantle the sink and pipes.’

Large blockages are often caused by cooking fat that’s been poured down the sink. This causes food particles to stick together, creating a blockage in the pipes which can be difficult to clear.

Most plumbers will charge by the hour for a job such as a sink that fails to drain, so a blockage that’s hard to clear will cost more. If you think it’s your drains that need clearing, follow our tips to hire drainage contractors.

Prevention and cost-saving tips

Avoid bad sink blockages by never disposing of cooking fats down the sink. Instead, allow the fat to cool and then scrape it into the bin.

Make it easier to clear blockages by asking your plumber to install a ‘rodding eye’. This gives you access to pipes at the bottom of the sink without having to take everything to pieces. ‘With a rodding eye, it will take the plumber less than an hour to clear,’ Danny says. ‘You could even have a go yourself if you wanted to save money.’

3. House has no heating or hot water

Every homeowner’s nightmare – the boiler fails and there is no heating or hot water. The following advice is based on a standard combi boiler in a small home.

How to solve the problem

Your plumber or heating engineer will need to investigate and find what’s causing the lack of central heating and hot water. Nobody other than a Gas Safe registered engineer should attempt to repair your boiler. Find out more in our guide to what to do if your boiler breaks down.

Which? Trusted Traders endorses boiler engineers throughout the UK, for all your central-heating needs.

Prevention and cost-saving tips

Before calling out a heating engineer, you can investigate the issue yourself.

Danny advises you to ‘check all the simple things first’:

  • Is the boiler turned on?
  • Check the gauge – is there enough pressure? Each boiler type will have an optimum pressure – check your manual for this. As a rule of thumb, the gauge should show a reading of between 1 and 1.5 bar of pressure when the boiler is cool. If the pressure gauge is low, you can add water to the system until it reaches the correct pressure. If it’s too high, you can vent the radiators to restore the system to the correct pressure yourself. Look for tutorials for this online, and see our guide on how to bleed a radiator. ‘But, if you’re not sure what to do, it’s best to call a Gas Safe-registered boiler engineer,’ Danny says.
  • If there’s an error message on the boiler display, check the fault code in your boiler’s manual or look online. Sometimes it’s possible to fix the problem without having to call out an engineer.

If you do need to call out an engineer, be aware that most gas fitters will charge by the hour for this type of work. Avoid paying more than you need to by clearing the area around the boiler and radiators before the engineer arrives. Find out more about gas-combi boiler checks and common problems.

4. Retrieving small items from waste pipes

Another common call-out for plumbers is recovering precious items that have fallen down a waste pipe in the kitchen or the bathroom basin – often jewellery such as rings or earrings. Sometimes blockages aren’t so precious: ‘I once found a rubber duck,’ Danny told us.

How to solve the problem

Danny says: ‘Never run taps or flush a toilet should you lose a small item, such as a ring, down the drain. The jewellery could be washed into the main drain, which will cause the job to take longer, cost more, and dramatically reduce the chances of retrieving the item.’

Your plumber should be able to get the item back for you. The length of the job will depend on how far down the drain it has gone. If it’s near the top of the drain it could take less than an hour, but Danny suggests it should never be more than three hours.

Prevention and cost-saving tips

‘Give the plumber good access by clearing all areas underneath and around the sink,’ Danny says. ‘This will prevent time being wasted and costs mounting up once the plumber has arrived.’

The best method is to stop small items going down the drain in the first place. Make sure you have sink strainers to catch items such as toothpaste lids, small jewellery, or hair – particularly long hairs, as these can cause blockages.

Danny says: ‘When hair goes down the drain, it doesn’t drain away with the water, so it builds up. When it mixes with shampoos and soap, it solidifies. Bicarb of soda can help break it up, but it’s best to stop it going down there at all.’

Another possibility is for your plumber to fit a grate to the waste pipe to prevent items being lost down the sink. Ask your plumber for details.

5. Leak through the ceiling

Our final problem is a water leak coming from an upstairs bathroom and passing through the ceiling to the room below. Danny told us: ‘The sealing on baths wears away over time, and water from a shower will go down the side of the bath. Often a small leak will create a reservoir over time. It might flood down in one big whoosh, but it may have built up over days.’

How to solve the problem

The first thing to do is turn your water off to prevent any further leaks. If you have isolation valves, you can turn these off to isolate the bathroom from the rest of the system. Otherwise you’ll need to turn off the main stopcock. Find out more in our guide to how to stop a water leak.

When your plumber arrives, let them know where you think the leak is coming from. ‘Time spent looking for the cause of the leak will add time to the job,’ Danny says. ‘If you have a suspicion about the cause, or have noticed any damp patches, tell your plumber at the outset to avoid wasting time.’

Prevention and cost-saving tips

‘Prevent a small problem from turning into a big one,’ Danny says. ‘Run your hand around all accessible pipe joints in the bathroom every six months or so. The leaks that cause damage are often those caused by a small drip that's been left a long time.’

He advises: ‘Know where your stopcock is. Turn it on and off every six months so to make sure it doesn’t get stuck. Never open it fully; always turn it a quarter turn back from full. This should avoid limescale building up around the spindle.’

Danny’s final tip is to ‘keep an eye on the seals around the bath where there’s a shower above. In my experience, most bathroom leaks originate there.’

If you need to find a reliable plumber, Which? Trusted Traders has endorsed businesses in your local area.

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