Senate Bill 9, which would allow up to four housing units on lots currently zoned as single-family in California, was just approved by the state legislature by a huge margin: 45-19.

A recent U.C. Berkeley study predicted that Senate Bill 9 could yield as many as 714,000 new homes in California. That would be good news for a state with a severe housing shortage, but the broader implications of SB 9 are enormous. Here’s one: The ability to split single-family lots into up to four separate units could make suitable properties exponentially more valuable. Literally, and overnight.

The bill still has to be approved by Governor Newsom. But a bigger question might make the sweeping legislation entirely pointless. In a drought-stricken state where there’s not enough to go around for the current population, where exactly would California get the water for all those new homes?