(1) All sanitary fittings shall be substantially made, shall be constructed of corrosion-resistant material, shall be impermeable to water, and shall be finished with a smooth, free from all flaws or blemishes.

(2) All sanitary fittings may, prior to their being put into use, be tested by, and shall be subject to, the approval of the local authority.

(3) No soil-water fittings shall be encased in wood other than absorbent material.

(4) All soil-water fittings shall be of vitrified earthenware, glazed porcelain, fire-clay or vitreous china, all having a glazed finish, or shall be of any approved impervious material.

(5) All waste-water fittings shall be of materials specified in subsection (4) or of cast iron, enamelled mild steel or stainless alloy.

(6) The provisions of this section shall not apply to sanitary fittings already installed at the date on which it comes into operation unless such fittings are in, at the said date, or thereafter have fallen into, such a condition that their continued use constitutes or is likely to continue a nuisance or a health hazard.