You may come to grief if you rely upon Zillow. You have to know how the Zillow algorithm works. They take tax data and sales figures from the property appraiser's office, manipulate it and adjust an area +/- % and apply it in a blanket manner to an area. And therein is the problem.
Zillow has no way of knowing whether a recent sale was the short or repo sale of a vandalized bank owned property to a vulture investor. Similarly you could have a situation where properties on one side of a road are waterfront or backing onto a railroad or Interstate and the other side isn't. Obviously prices on either side of the road will vary markedly. Or you could have a house where the owners have lived for decades in a "Save Our Homes" property tax increase limitation jurisdiction. Or someone who has added room/s, patio, garage or whatever to a property.
However, Zillow are very good at surreptitious self promotion, but then I'm sure you've all noticed that with many American products, the more it's advertized, the worse it actually is. Ask an experienced realtor what he or she thinks of Zillow.