No cellar drain or drain from stables or surface water of any kind shall be connected with any drain emptying into public sewer, except through the interposition of a proper sand well, made easily accessible for cleaning. Where cellar drains are set so low as to render it possible that backwater from the sewer may under some circumstances be forced into the cellar, they shall be provided with an approved form of check valve in addition to sand well as above.
(1967 Code, § 16-32) Penalty, see § 10.99