This is easily the most I have watered lawn and garden here in SVT since moving here in 2014, also the brownest I have seen the lawn and that is with some rain here and there.
I think a big part of the brown lawns and dry gardens has been the very low RH and DPs for most of the summer. The evapotranspiration I'm sure has been off the charts when you combine very low RH, sun and wind. The top 4-6" of soil has been getting sucked dry very quickly. Before this recent stretch every day seemed to be a Chamber day with sun and low dews. The other week I had 1" of rain and was watering again in 2 days. Even 1" of rain really did nothing to my grass, just kept it from getting browner really. I think many of our summers the past 15 years have been so humid, that moisture was retained in the soil much more so after a rain event.
As was mentioned also, soil composition plays a big part too. Obviously it has been dry for a big part of the region as well as per the map posted.