Water storage tanks are necessary for many reasons in Napa County. Water tanks are required to be permitted with the Napa County Building Division when they store above 5,000-Gallons and or the ratio of height to diameter or width does not exceed 2:1.
Go to the Napa County Permit Applications
The Napa County Building Division manages the construction permit process that includes the permit submittal, review, issuance, inspection and document retention. The property owner or an authorized licensed contractor are the only individuals who can legally sign the application for permits.
Water tanks above 5,000-Gallons are required to be anchored to a cement pad due to the seismic nature of Napa.

Napa Sonoma Water Tanks are designed for durability with quality materials that can be used for multiple applications in accordance with Code. Our optional engineering packages for permits include a cement ring base per tank model as well as a California engineer wet-stamp cover letter for each project.
According to the Napa County Building Code (Link):
13.04.070 – Water storage tank requirement.
An individual water supply system having a sustained yield of at least one gallon but less than five gallons per minute shall have a water storage tank installed. Each storage tank shall have a minimum capacity of three thousand gallons for each dwelling unit. Each application for a permit shall be accompanied by a fee established by the board of supervisors. The installation of the water storage tank cannot be made until after the director approves the installation and issues a permit for the installation.
(Ord. 1159 § 1 (part), 1999)
(Ord. No. 1374, § 4, 9-11-2012)
15.32.250 – Table B105.2 is added—Minimum fire flow.
