The UK’s drinking water is among the best in the world and WaterSafe is urging householders to ask their plumber one simple question to keep it that way.

WaterSafe, the UK’s leading online register of approved plumbers, advises anyone having plumbing work done in their property to ask one vital question: “Which solder are you using?”

The call is highlighted in a new WaterSafe podcast, which shared the hidden danger of lead from solder in domestic drinking water systems.

Solder is material plumbers use to join pipes to create strong, watertight connections. The crucial point? For pipes carrying drinking water, it must, by law, be lead-free.

Lead solder has been banned for use on cold water systems since the 1970s. If it’s used on water pipes, tiny amounts can dissolve into the water you drink and cook with. This is especially dangerous for babies and young children as lead exposure can harm their development, affect their IQ and even cause behavioural issues.

Despite this long-standing ban, WaterSafe Director, Julie Spinks, reveals in the podcast that research shows two-thirds of plumbers still carry lead solder in their vans, alongside lead-free alternatives. While lead solder can legally be used for systems like central heating, if a plumber has it at all, there remains a risk it can be accidentally used on drinking water pipes.

Julie said: “Even a small, unintentional mistake can have significant consequences. I’ve seen cases where lead levels in drinking water have been found to be extremely high due to lead-soldered joints, even in places like schools. It’s a completely preventable problem, and by simply asking your plumber, you can help protect your home.”

Ruben Duggan, an award-winning plumber, echoes the concern: “In the heat of the moment, with floorboards up and water needing to be reconnected quickly, it’s a terrifying thought that a plumber could accidentally pick up the wrong solder. That single joint, once made with lead, can affect the drinking water system forever.”

If you have a plumber working in your house, WaterSafe urges you to ask which type of solder they are using and confirm they are using lead-free solder for drinking water pipes. This simple question can protect your family’s health.

Lead-free solder usually comes with a green label, whereas lead solder usually has a red label.

To find out more, listen to the WaterSafe podcast on lead-free solder: https://bit.ly/lead-free-solder-podcast.