When I add a trailer I took out 500 liters 250 is not enough and you need to put the weight off the water in the middle of the trailer I didn't and it ruined my car and you need a very good jet wash one that will suck the water out not gravity fed you need to find out where the bin man start in the morning you also need a foul drain to put the dirty water down any rubbish thats in the bin when bean empty put it in a bin bag and put it back in the bin i do up to 90 bins a day i only 5 days a month did have 15 days a month but I sold the rest because I couldn't do everything I prefer to do windows but does 5 days I do on the bins elp out big time in the winter when it's raining all the time hope this helps really need to speak on the phone about it not good puting it down in writing e-mail your number to me and I will ring you a lot more to know