Should You Replace Old Lead Water Pipes in a Kingston Home?

Lead was the standard material for water supply pipes in Britain until the 1970s. It stopped being used in new work after that, but a great many pipes fitted before then are still in the ground and still in service. Kingston upon Thames has a substantial stock of Victorian, Edwardian and inter-war housing, so it's a reasonable question for any owner of an older property to ask.

This is a general guide to how the issue works. Whether your particular home has lead pipework, and what condition it's in, can only be established by looking.

There are two separate sections, and they have different owners.

The communication pipe runs from the water main in the street to the boundary stop tap, typically in a small covered box in the pavement. This section is the water company's responsibility.

The supply pipe runs from that boundary stop tap, across your garden or drive, and into the property to your internal stopcock. This section belongs to the property owner — so if it's lead, replacing it is the homeowner's decision and cost.

Inside the house, lead is most often seen in the short run between where the supply enters and the internal stopcock, usually under the kitchen sink or in a hallway cupboard. Internal lead plumbing beyond that point is less common, as most was replaced during past refurbishments.

Find the pipe feeding your internal stopcock and look at it before the valve.

• Colour: lead is dull grey, not the orange-brown of copper or the grey-white of modern plastic.
• Scratch test: gently scrape the surface with a coin. Lead reveals a bright silver streak underneath. Copper shows copper.
• Sound: tapping it gives a dull thud rather than a metallic ring.
• Joints: lead pipe is typically joined with bulbous, hand-wiped solder joints rather than the neat compression fittings used on copper.
• Shape: lead is soft, so runs are often slightly irregular or bowed rather than dead straight.

If you're unsure, don't guess — a plumber can confirm it in a couple of minutes, and your water supplier can advise on the section they own.

Water quality. Lead can dissolve into drinking water, and UK drinking water standards set a strict limit. Water companies dose supplies with orthophosphate, which forms a protective lining inside lead pipes and substantially reduces this. It's an effective measure, but replacing the pipe is the only way to remove the source entirely. If you want to know what's actually coming out of your taps, your water supplier can arrange a sample test — that is the right first step rather than acting on assumption.

Flow and pressure. This is often the driver in practice. Old lead supply pipes are frequently narrow — sometimes the equivalent of half an inch or less — and decades of internal deposits reduce the bore further. That limits how many litres per minute reach the house, which shows up as a shower that fades whenever a tap is opened, or a combi boiler that can't reach its rated output. Replacing a tired lead main with 25mm or 32mm MDPE often transforms flow throughout the property.

Reliability. Lead is soft. It deforms under ground movement, and old joints fail. A supply pipe leaking under a garden or drive can run for a long time before anyone notices, and on a metered supply that's a bill nobody wants.

Selling or renovating. A lead supply pipe is routinely flagged in surveys. If you're re-landscaping the garden, having a driveway dug up, or refitting the kitchen, that's much the cheapest moment to deal with it, because the disruptive part is already happening.

In outline, the work runs like this:

1. Survey. Confirm the pipe material, trace the route from boundary to property, check the internal stopcock position, and measure existing flow rate as a baseline.
2. Route planning. Decide between open-cut trenching and moling, a technique that pulls new pipe through a bore underground, which avoids most of the excavation across lawns and driveways.
3. Installation. New blue MDPE pipe, usually 25mm or 32mm, laid at the correct depth — normally at least 750mm — to stay below the frost line, with an external stop tap and a new internal stopcock.
4. Connection. The new supply is connected at the boundary and to the internal plumbing, then pressure tested, chlorinated where required, and flushed.
5. Reinstatement. Making good the ground, path or driveway.

Most domestic jobs are one to two days. The variables that move the timescale are the length of the run, what's on top of it, and whether the water company needs to attend to make the connection on their side.

• Ask your water supplier about their lead policy. Some run schemes to replace their side of the pipe, sometimes free, when the homeowner replaces theirs at the same time. Getting both sections done together is the only way to fully remove lead from the path, and it's worth a phone call before booking any work.
• Have the water tested first if water quality is your motivation. It turns an assumption into a fact.
• Check the whole run. Replacing the internal section while leaving lead in the garden achieves very little.
• Confirm who reinstates what. Block paving, resin drives and mature planting all need to be in the quote, not discovered afterwards.
• Check for other services — gas, electricity and telecoms — along the route before anyone digs.
• Ask about the boundary connection and whether a supplier appointment is needed, as that often sets the date.
• Get it in writing: pipe size, depth, route, reinstatement, guarantee.

It's worth having someone look if you've identified grey pipe at the stopcock, if flow rate is poor throughout the house, if you have unexplained high water usage on a meter, if a survey has flagged lead, or if you're planning groundworks anyway and want to make the decision once. A survey gives you the pipe material, the route, the current flow rate and a realistic price — and sometimes the conclusion is that the lead section is short, sound and not your bottleneck.

Maxfix provides water mains and lead pipe replacement and ongoing plumbing maintenance across Kingston upon Thames and South West London, including stopcock replacement where an old valve is seized or restricting flow.

Call Maxfix on 020 3488 0912 or request a free quote. We'll tell you what you've actually got before recommending anything — that's the approach that's made us a trusted plumber in Kingston.