Has JK Rowling ever explained why she chose the address 4 Privet Drive?

Question

Mr. and Mrs. Dursley, of number four Privet Drive, were proud to say that they were perfectly normal, thank you very much

Has JK Rowling ever explained why she chose the address 4 Privet Drive?

I am curious both as to the street and the number.

Answer 1

The street name is a reference to the privet bush, a common feature enclosing suburban English gardens

The name of the street where the Dursleys live is a reference to that most suburban plant, the privet bush, which makes neat hedges around many English gardens. I liked the associations with both suburbia and enclosure, the Dursleys being so smugly middle class, and so determinedly separate from the wizarding world.

The number four is just one that Rowling doesn't like

For no very good reason, I have never been fond of the number four, which has always struck me as a rather hard and unforgiving number, which is why I slapped it on the Dursleys’ front door.

Both of the above quotes come from J.K. Rowling's essay "Number Four, Privet Drive", which was first published on Pottermore.com during its initial launch on August 15th 2011. The essay has moved around a bit online since then, but can currently be read here.