Why you shouldn’t swim after it’s rained

Ever hear the warning ‘don’t swim after it’s rained’?

That’s because the rain runs off our paved streets directly to the ocean via the network of stormwater drains, canals and rivers every city has, carrying with it all the nasties accumulated along the way. Then there’s the periods of heavy rain… when water management authorities may decide to ‘bypass’ the sewerage system and release effluent directly into waterways!

The major problem is permeability.