How to take part in the Water-Blitz

How to register

Each water-blitz event has a time limited log in period, so please register your interest beforehand by emailing You will be added to the contacts database and receive an email prompting you to register / log in with Freshwater Watch a few weeks prior to each water-blitz the event. This gives us time to package and post out the test kits. Each test kits comprises 1 plastic tube containing a powder to test for nitrates (N), 1 for phosphate (P), 1 colour matching card to interpret results for each of the P & N tests, and 1 measuring beaker.

Test kits are provided free of charge for the Thames Water-Blitz, as long as we can maintain funding.  Contributions to Wild Oxfordshire to support the Water Blitz are welcome and will enable us to do more with these funds.

Where will you take your samples?

When you register on the Freshwater Watch site you can name 2 sites that you’d like to sample. If you have the time and would like to test more than 2 sites please contact Hilary to discuss this. You can look at last year’s result’s to identify sites that have been tested in the past. We encourage you to find new sites (different types of sites) that you can conveniently test again at the next water-blitz, so preferably ones that don’t normally dry out in summer, you have any necessary permission to access and can so safely.

You will need to accurately record your sampling location. You can either do this by hand, using an Ordinance Survey map (if you need help with this go to, use a smartphone to determine your latitude and longitude, or the online map service on the FreshWater Watch website. Alternatively use to get your grid reference and other location information.

What will you record and how?

There are excellent guidelines on health & safety, and how to collect water samples and use the test kits on the Freshwater Watch site, which you will be able to view after you’ve registered. Collecting the water sample doesn’t involve wading into water of any depth – a variety of collecting methods can be used, ranging from a small bucket on a rope to a plastic bottle taped to a stick. A telescopic decorating pole works very well (with a small plastic container on the end), compact but providing the range needed for different sites. The P tests take 5 minutes to react, the N test 3 minutes. Timing is critical, so make sure you have a watch or phone with you.

As well as taking P and N readings you will need to record the location, a site name, the date, time, number of participants, type of freshwater body and some observations about the appearance of the water and its surroundings. If you can take a photograph as well that’s a bonus!

All this data can be recorded and uploaded directly using the ‘phone app (available on the Freshwater Watch website). However we strongly advise you to keep a paper copy as well, so you have a personal record of your data and a back-up in case of mishaps. Forms can be downloaded from the Freshwater Watch site. If you can’t manage to upload your records yourself you can post these forms to Hilary at Wild Oxfordshire, or use a local volunteer.