It seems you have misunderstood. This point is not about supply of water, it is about supply of dollars in a given wallet. Doesn't matter how much water is in supply: if someone cannot meet the price, they won't have access.
Any time there is a minimum price on something, people who cannot afford that price won't receive that thing. When that thing is water, they will die. Seems pretty straightforward to me.
"With new construction halted and Bolinas's desirability unabated—or enhanced—after the moratorium, housing became pricier. In 1979, to create more affordable housing, the District allowed property owners to build second units on their property. Today [2007], property owners waiting for a chance to develop outnumber property owners with [water] meters, and homes can easily fetch $1 million."
You will find it difficult to quantify a dollar-value of the damage done to people who would like to live in a particular place but have been locked out due to artificial constraints on housing supply. That's why it's such an effective strategy.
If you don't know of anyone in California who has died of thirst because of water cost, please don't assume that absence of evidence is evidence of absence.
