I would not normally bother to dignify this sort of comment with a response but I feel you are really missing something here.
It is a shame if this has been your experience of every motorhome that has ever visited Conil but I sincerely doubt this is actually the case.
We have been on the road for three months now and have met a considerable number of motorhomers who have, without exception, contributed in some way to the towns and economies in which they stop and who have demonstrated great care and concern for their surroundings.
If towns like Conil are foresighted enough to provide clearly signed spaces where motorhomes can park - even if it is only for low season - and ideally some basic facilities (ie a tap and a drain), people will not park anywhere which is obstructive or a nuisance for the local community and their presence will benefit it.
Although we were clearly not welcome to stop overnight, far from freeloading, we shopped in your supermarkets (including, incidentally, buying drinking water since you raise that as a particular grievance), bought petrol in your petrol station, visited your tourist office and therefore contributed towards the continuing employment of the people of your town. Had we felt welcome to stop in your town somewhere, your cafes, bars and small shops would have also benefited from our custom, as Tarifa's did later in the week
Before making comments like this, you would be wise to consider that the people who are currently in this part of Europe, at this time of year, in motorhomes, are those who live in them for 6+ months of the year, who will stay for while in places where they are made welcome and who, having retired or otherwise found a way to fund this lifestyle long term, also have money to spend. Money which the local community would not otherwise benefit from in low season when there are few other tourists.
Given that, as has been reported in the news only yesterday, Spain is the only major economy in Europe still in recession, I would have thought that you would be making every effort to welcome to your town, people who will contribute towards your country's economic recovery.
I don't know you, I don't wish to start a flame war with you and I will not enter into any further discussion with you but I think you should reconsider your opinion of motorhomes and the positive impact they have on your town or, at the very least, get to know some of the people who live in them, before making comments of this nature.