Got to be mind full filling up around here at times, As our brackish saltwater table is not much more than a meter or so down, our local servo's tanks have so much water ballast in them to stop them floating out of the ground [ so I'm told ] , being so close to the river and sea ..
Had a few local servo's [ sites were returned to vacant blocks for decontamination ] tanks rust and leach fuels into the sand / water table over the years ..one Shell servo site was being treated 24/7 for about 15 years, the old Mobil site was done twice for close to 5 or 6 years total and the BP depot was done the same for a number of years .
We never fuel up straight after the fuel trucks been or at the end of a very busy period as the fuel gets low, learnt our lesson, .
After we got 80lt of fuel from that original Shell site [ Interesting to note its reopened as a new Shell servo again all these years later ] and got about 2klm down the road and the motor stopped, Filled a 2 ltr coke bottle with fuel from the tank, let it settle and about 3/4 of it was dirty water . They denied it and we never did get our money back ..