Urination & Diving

Question:

I am new to diving. Every time I dive, I always feel I have to pee. Is this normal? Is it alright if I pee in the water? Will it kill the coral reefs?

Answer:

It is completely normal to want to urinate shortly after starting to dive. On land the force of gravity causes blood to pool in our legs. This can be 500-800mls of blood. When our body is totally immersed underwater it is weightless and gravity no longer causes this effect. The pooled blood will shift and be distributed over the whole body. Our body will then produce more urine to reduce this extra load and we feel our bladder filling.

Urinating into a wet suit, especially when diving in very cold water towards the end of the dive can be a heart-warming experience (or maybe better stated as suit-warming! Ed.) Some of this urine will be flushed out into the seawater. (It is always important to rinse the wet suit out between dives!) One person urinating into the sea will have little effect on the coral reef but if hundreds of people urinate on the same reef day after day then the high nitrogen load can damage the delicate corals. If you were diving on a popular diving site frequently dived by many divers it would be beneficial to the reef to try and avoid urinating till after the dive.