Bonds of any flood control and water conservation districts, or any zone thereof, having an assessed valuation on taxable real property of not less than one million dollars ($1,000,000), county, city and county, city, metropolitan water district, municipal utility district, any special district established by and within any municipal utility district, transit district, rapid transit district, including sales tax revenue bonds of that district of the State of California (herein referred to generally as public corporations) except the bonds of any particular

such public corporation which may be declared ineligible for investment by commercial banks by regulations of the commissioner.