My municipal city water pH is over 9 out of the tap, by design.
Several North American municipal water utilities adjust water pH upwards, to the 8.8 - 9.4 range, in order to reduce lead, copper, and other metals that can corrode/dissolve into drinking water. Such municipalities include: San Francisco, Flint, Denver and Westminster, Boston and the 60 other communities served by the Massachusetts Water Resources Authority, and the Canadian cities of Ottawa, Durham, London, Thunder Bay, to name a few.
Refer to:
ottawa.ca
Español The water Denver Water delivers to customers is lead-free. And for decades, Denver Water has protected its customers from the effects of customer-owned lead-containing water service lines and household plumbing in a variety of ways, including adjusting the pH of the water it delivers to...
www.denverwater.org
Kim, E.J., Herrera, J.E., Huggins, D., Braam, J. and Koshowski, S. (2011). Effect of pH on the concentrations of lead and trace contaminants in drinking water: a combined batch, pipe loop and sentinel home study. Water Res., 45(9): 2763–2774.
Lytle, D.A. and Schock, M.R. (1996). Stagnation time, composition, pH and orthophosphate effects on metal leaching from brass. Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, Ohio (EPA/600/R-96/103).