<blockquote>Although the researchers were unable to confirm exactly what fraction of visitors were choosing to quietly relieve themselves in the water rather than making the shivery trip to the changing rooms, the results suggest that the urine content was being topped up several times each day.</blockquote>
via <a href="https://www.theguardian.com/science/2017/mar/01/how-much-pee-is-in-our-swimming-pools-new-urine-test-reveals-the-truth?CMP=twt_a-science_b-gdnscience">How much pee is in our swimming pools? New urine test reveals the truth | Science | The Guardian</a>.