renting with pets

A couple of weeks ago, I was in Brussels to search for a townhouse, we visited 20 places in two days and in general pets was not a problem (we have a dog). There was only one landlord who refused to accept the dog. Two of the landlords was a bit reluctant but we ended up renting one of those places anyway, most landlords seemed willing to compromise. It might be a little different when renting apartments.