I don’t do it; seen too many nightmarish things happen once water is reintroduced to homes that have been vacant or winterized. Numerous leaks in supply and DWV lines (dried seals, gaskets that shrink once dry then come apart when wet again). What I have found over the years is often when a house is vacated if there were plumbing issues, these do not get fixed as the simplest and cheapest method is to say it has been winterized when all that has been done is the water turned off by the Water company, meter is closed and locked, tagged or banded with warnings NOT to use any of the appliances, plumbing and electrical. Basically, the home is NOT ready for inspection. Some agents get their panties in a wad if you won’t turn on the water, throw circuit breakers but if and when something goes awry they will immediately throw YOU under the bus. Get the home ready for inspection, all utilities ON and we will come back. If the buyer insists on doing it that day w/o utilities I defer any responsibility for things not working later (if I can’t inspect it I sure as heck am not going to pay for any faults) and I do a visual inspection only and make certain they know that and it is in the report multiple times (at every fixture and noted in the foot notes of my summary. I recently did a home that had been “winterized” which consisted of turning off all the water and filling all the traps with automobile windshield washer liquid (non biodegradable type).