Water Quality Testing for Open Water Swimming

As open water swimming continues to grow in popularity across the UK, so too does the need to ensure that the rivers, lakes, and coastal waters we swim in are both safe and clean. Unlike swimming pools, which benefit from regular treatment and monitoring, natural bathing waters are exposed to a wide range of environmental influences that can quickly impact water quality. Runoff, sewage discharges, and naturally occurring bacteria are just a few of the potential risks that can pose serious health concerns for swimmers if left unchecked. For anyone responsible for managing or providing access to these waters, effective testing and monitoring is an essential step in protecting public health.

In this article our water safety experts take a closer look at water quality testing for open water swimming, highlighting the regulations that apply to natural bathing waters in the UK and why they matter. We’ll explore when and how water should be tested, what parameters are important, and how results should be interpreted to ensure compliance and safety. The guide also considers the practical aspects of water sampling, the importance of routine checks during the bathing season, and why professional laboratory analysis is often the most reliable way to safeguard swimmers and meet legal obligations.

Why is testing of water quality important for natural bathing waters?

While many people head for their local swimming pool when they want to swim, others who live near lakes, rivers or the ocean might decide to take a more natural dip instead. However, the question then arises about whether water quality issues make open water swimming or bathing safe. Swimming pools are regularly treated with chlorine and tested to make sure the water is safe to swim in, but this doesn’t happen with natural water sources.

We’ve all read news reports about contaminated rivers and lakes, uncontrolled sewage discharges and such like, so if you have anything like this on your property or choose to open it to the public to use, you do have regulations you must meet to ensure people can use it safely.

Which water quality regulations apply to open water swimming?

In the UK the Bathing Water Regulations 2013 along with an amendment in 2018 are in place to provide guidance to those who wish to allow swimming in inland water anywhere in the UK. You should abide by these guidelines and check whether there are any other specifics available locally that may provide further guidance or specific requirements on water quality and safety.

When should the quality of open water swim sites be tested?

You should always check water quality before the bathing season begins. This typically runs from May to September. You can check details and dates for the current year online, which are available via the official government website operated by the Met Office.

Following your initial water quality testing, you should then check the water every two to four weeks during the season, more if you suspect water quality may have changed. Changes can swiftly occur in open water; hence why regular testing is required to ensure you are aware of anything that may influence the quality of the water. If you are planning any event in the water, test again just prior to the event’s start. If the tests highlight problems, the event would need to be cancelled or postponed.

You should also visually check the water and make sure you are familiar with how it normally looks. This will make it easier for you to identify any potential issues each day. If anything looks out of the ordinary or suspicious, you can then test the water again. You should also test whenever it rains, since water running off the surrounding ground can often carry contaminants into the lake, river, or stream.

Finally, the close of the bathing season is the ideal time for one last check of the season.

Where should you take water samples for testing from?

Where you take your water samples from will vary depending on various factors. Follow current guidance to determine how many samples you need to take and where from. You’ll need to test the water at all entry points, along with any inlets to the body of water. Since no two bodies of open water are identical, the requirements here will depend on your surroundings. Hence why it is essential to follow all guidelines to ensure you are correctly sampling and testing the water.

Most samples are taken 30cm beneath the surface of the water, except for algal blooms such as Blue-Green algae which are on the surface.

Water samples should be tested at an accredited laboratory within 24 hours of collection

The testing laboratory you use should provide full instructions on how to take the samples, advise on any protective equipment, along with providing sterile bottles and other equipment to do this with. Water quality testing of open waters should typically cover appearance, odour, phenols, E. coli, intestinal enterococci, and other factors including pH. All parameters tested will receive results that put them into one of four categories:

• Excellent
• Good
• Sufficient
• Poor

Results falling into the Poor category are deemed an automatic fail.

Do you know the quality of your water for swimming or bathing?

If you don’t know the quality of the water you swim in, or if you intend to open those waters for people to use, it’s time to test. Follow the Bathing Water Regulations identified previously and take note of any other legislation that is relevant for your country or location, to ensure you are doing everything required of you. Testing is one of the best ways to keep your open water swimmers safe from the effects of poor quality water.

Regular testing and effective monitoring are the most reliable ways to ensure that natural bathing waters remain safe for swimmers. By following the Bathing Water Regulations and carrying out routine sampling, it is possible to identify potential risks early and take the right steps to protect public health. With open water swimming becoming ever more popular, the importance of managing water quality responsibly has never been greater.

Expert water quality testing for open water swimming and natural bathing waters

At Water Treatment Services, our specialists provide a full range of water quality testing and laboratory analysis solutions designed to support owners and operators of open water swimming sites and other natural bathing areas. With expert advice, accredited testing, and nationwide coverage, we can help you manage your waters safely, meet regulatory requirements, and give swimmers the confidence that the water they use is clean and well managed.

Contact us today to learn how our expert water quality analysis services can help you keep your water safe.