All public domestic water wells constructed prior to the effective date of this chapter which do not have an effective surface seal shall be provided with a concrete base which meets the requirements of Section 13.16.450 and shall comply with the requirements of Sections 13.16.480 and 13.16.490. They shall also have an annular seal two inches thick which extends down the outside of the outermost casing not less than three feet from the ground surface. A public domestic well which, within one year after the effective date of this chapter, does not meet all the requirements of this section shall be deemed a public nuisance within the meaning of Section 13.16.240. It is unlawful to maintain such a nuisance. (Prior code § 7805)