Rick is correct. I live in Florida, have city water, etc and have seen that soapy hose phenomenon often. The chlorine/dissolved oxygen and other gases hit a different temperature/pressure once released from the hose, especially if you see it "spitting" when it first comes out....It looks like soap but it's gas bubbles coming out of solution. Has not harmed my plants or my dog in any way. Hope this is also your situation. Fill up a clear glass with that "soapy" stuff, as all the gas dissolves out, the water should clear up...not leaving any white thick goop behind like you'd imagine with foamy soap.
