If you follow the letter of the law, (at least with my local water authority) you should dump down a foul drain, i.e Toilet or Sink, or the grate outside the kitchen window, i was told dumping it anywhere else leaves me open to bieng fined.
Dene
Good point. It’s the environment agency that fines you. Phosphates that are often found in cleaning products are really bad for the environment, fish especially. The environment agency is duty bound to prosecute and fine, so there is no slap on the wrist or warning.
In 1994 they had 24,000 cases of people/companies polluting watercourses. However most of these were farmers and ships/boats.
If you use a portable, tell the custy it has to go down the foul water drain or toilet. Dumping in storm water drains, you are probably being watched by the nieghbours and it only takes one phone call from a vigilent, enviromentally aware busybody and your In the poo.