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What Are Safe Chlorine Levels in Drinking Water?

March 8th, 2020

Last updated: July 12th, 2022

There are few things more important in life than safe drinking water. Chlorine is long established as an effective and inexpensive form of disinfectant, and regulatory limits exist to control its safe use in drinking water. Wha is a safe level of chlorine in drinking water? Is chlorine harmful in drinking water? We answer your questions in this guide.

Decisions have been made on how much chlorine is added to water after extensive research, testing and reviews of health data.

Why is Chlorine Added to Drinking Water?

The primary use of chlorine in drinking water is to destroy bacteria and viruses that can enter a water system, and chlorine has been adopted as the only large scale method used for residual protection of drinking water in the UK.

However, it is required that drinking water contains detectable levels of chlorine and that these are controlled, as some people are more sensitive than others to chemicals and changes to their environment. Patients requiring dialysis treatment, for example, are exposed to large amounts of water and so dialysis centres must treat the water to ensure all chemical disinfectants, including chlorine, are removed.

If you are wondering “is chlorinated water safe to drink?” Then the answer is usually “yes” if you are drinking from a tap or municipal supply, but only if the water has been labelled as safe drinking water. Don’t take any chances with water that has not been tested.

For example, if you were to consume significant amounts of pool water then you may well experience health complications. Poolfence has a brilliant guide on the potential dangers of consuming water that is this heavily chlorinated.

Alternatively, if you consume water that doesn’t have the benefits of chlorine treatment then it could carry water-based diseases such as Legionella.

Safe Chlorine Levels For Drinking Water in England and Wales

In England and Wales, chlorine levels are maintained by individual water companies, but typically the level of residual disinfectant in the form of free or combined chlorine is 0.5mg/l or less. It is possible that higher levels may be detected during maintenance, but this should be a short term deviation from the average reading. If the unusual taste persists you should contact your local water company immediately.

The World Health Organisation set a health-based guideline on how much chlorine is added to drinking water worldwide. Their maximum chlorine value is 5mg/l in drinking water, however, in England and Wales, water companies have chosen to reduce this to well below 1 mg/l.

Given that water leaving a water treatment plant passes through miles of pipework as it is conveyed to your home or workplace, it is very likely that chlorine levels will vary at different points and from day-to-day, however, the long history of use worldwide – over 100 years – means you are unlikely to experience a change in level that will be harmful.


Does Chlorine Kill E-Coli in Drinking Water?

Yes, when chlorine is added to a water supply it forms a weak acid called hypochlorous acid which is effective at killing E-Coli.

Can You Drink Chlorine Water?

It all depends on the levels of chlorine. The WHO research shows it is fine in small amounts, drank as part of a water supply, but you should not drink water that has been chlorinated for a pool or a hot tub.

How Robinsons Facilities Services Can Help With Chlorine Levels in Drinking Water

If you are concerned about the chlorine levels in your water, we can test and monitor these for you, and even provide you with a water chlorination certificate. This shows the levels of chlorine in the water and can be a useful document when it comes to proving that you have monitored the water, for instance, if you wish to sell.

Our service ensures that levels can be controlled and monitored if there are any concerns, and regular testing will give you historical data to refer back to and a high level of confidence that chlorine levels will be acceptable. You can also contact your local water company and request a free water quality report.

Commissioning regular testing and monitoring of water systems ensures regulatory compliance, and can also save you money in terms of identifying leaks or inefficient systems. At Robinsons Facilities Services, we can also monitor and control chlorine levels in your drinking water, to ensure that any supplies accessible to employees and visitors are safe and legal.

Contact us today and we can discuss the design of your water supplies and the controls required to be implemented to ensure the safe ongoing use of drinking water containing detectable levels of chlorine.

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