How healthy is your local lake or pond?

Good water quality is essential for the many animals and plants that live in and around our lakes, ponds and rivers.
Unfortunately, water is easily affected by pollution from agriculture and industry, waste we throw away, and even pollutants in the air.
Animals living in the water can tell us a great deal about how polluted the water may be. Some species struggle to survive in polluted waters, while others are more tolerant.
By taking part in the OPAL Water Survey you’ll discover more about the health of ponds in your local area. By submitting your data online, you can use the OPAL Data Explorer to compare your results to others submitted across the UK.
The best time to do this survey is from May to November.
How to take part
- Step 1 – Print the documents in English below, or in Welsh, ideally in colour.
- Step 2 – You'll need a few household items (listed in the field guide) and some pH strips (available from most garden centres).
- Step 3 – Choose a suitable pond or lake. We've prepared a guide to help you find a pond.
- Step 4 – Tell us what you find using our simple online form.
Enter your results online
Once you've completed the survey, simply submit your results:
Downloads – what you need to take part
Survey pack
- Water Survey Booklet (PDF, 1.5MB)
Full instructions and invertebrate guide.

- Freshwater Invertebrate Identification Guide (PDF, 598KB)

- Amphibian Identification Guide (PDF, 367KB)

- Dragonflies Identification Guide (PDF, 197KB)

- Duckweeds Identification Guide (PDF, 215KB)

- OPALometer (PDF, 29KB)
A printable OPALometer for measuring water clarity.
Also available:
- Water Survey recording sheet (PDF, 124 KB)
Easy-to-print recording sheets (black and white).
By downloading this survey you agree to the terms and conditions for the OPAL Water Survey
Group leaders and schools
Download our group leader support guide, example risk assessment, and our new recording sheets for schools:
- Group leaders support (PDF, 388KB)
Group leaders may benefit from our support pack with information and ideas on planning a group event, and additional safety information from the Royal Society for the Protection of Accidents (RoSPA).
Children's activity sheets
Test your water knowledge and learn fascinating facts with our water activities for youngsters.
10 tips for healthy ponds
Create the perfect pond by following these top tips from OPAL scientists and Buglife.
- Pond tips (PDF, 134KB)
Show you care
Please respect our environment
Ponds and lakes are home to important creatures.
Biosecurity
A good biosecurity routine is essential to reduce the risk of spreading invasive species: