[M T]

In regard to the use of groundwater, you may be interested in a report that primarily compares water rates across the US.

IMO, this study is flawed in multiple ways: (1) it doesn't include all the water systems (for instance, it doesn't include any of the SF Peninsula between the middle of Sunnyvale to San Francisco except San Mateo)  (2) many of their numbers count water districts rather than customers served (areas of smaller districts dominate the stats, IMO) (3) I didn't see anything relating cost to average rainfall (4) the data include the same company name many times without indicating the location of the water district (other than the state it was in).

But, given the issues, some of its conclusions include
 (1)  "Surface water was often more expensive: All but one of the 25 most expensive systems relied on surface water, including seven systems that primarily purchased their surface water from other systems..."
(2) "Corporate systems were overrepresented: While only 11% of the 500 systems in the dataset were privately owned, 44% of the top 25 most expensive systems and 70% of the top 10 were owned by for-profit corporations."
(3) "California was overrepresented: More than half (52%) of the 25 most expensive systems were in California, whereas California systems represented just 18% of the 500 systems in the dataset. "
(4) "Water bills were unaffordable for low-income households in nearly all (93%) of the analyzed water systems."
(5) "Household drinking water bills rose 62% over the last decade... The 25 most expensive systems increased bills by an average of $637 in the past decade, a 124% rate hike. The 25 least expensive systems increased bills by $58, or 44%."

The rates for water ranged by a factor of 10 ($133/yr to $1416/yr(San Jose Water))

I believe the ability to use ground water is a consequence to being in an area whose rainfall is high relative to the water use. Generally water use is related to population, but farming in water-deficient areas (Calif. Central Valley) increases water use.

[M T]

In regard to the use of groundwater, you may be interested in a report that primarily compares water rates across the US.

IMO, this study is flawed in multiple ways: (1) it doesn't include all the water systems (for instance, it doesn't include any of the SF Peninsula between the middle of Sunnyvale to San Francisco except San Mateo)  (2) many of their numbers count water districts rather than customers served (areas of smaller districts dominate the stats, IMO) (3) I didn't see anything relating cost to average rainfall (4) the data include the same company name many times without indicating the location of the water district (other than the state it was in).

But, given the issues, some of its conclusions include
 (1)  "Surface water was often more expensive: All but one of the 25 most expensive systems relied on surface water, including seven systems that primarily purchased their surface water from other systems..."
(2) "Corporate systems were overrepresented: While only 11% of the 500 systems in the dataset were privately owned, 44% of the top 25 most expensive systems and 70% of the top 10 were owned by for-profit corporations."
(3) "California was overrepresented: More than half (52%) of the 25 most expensive systems were in California, whereas California systems represented just 18% of the 500 systems in the dataset. "
(4) "Water bills were unaffordable for low-income households in nearly all (93%) of the analyzed water systems."
(5) "Household drinking water bills rose 62% over the last decade... The 25 most expensive systems increased bills by an average of $637 in the past decade, a 124% rate hike. The 25 least expensive systems increased bills by $58, or 44%."

The rates for water ranged by a factor of 10 ($133/yr to $1416/yr(San Jose Water))

I believe the ability to use ground water is a consequence to being in an area whose rainfall is high relative to the water use. Generally water use is related to population, but farming in water-deficient areas (Calif. Central Valley) increases water use.