Section 18(2)(ii) in The Merchant Shipping (Crew Accommodation) Rules, 1960
(ii)a wash basin of vitreous china or other equally hygienic and durable material, which shall be fitted with an efficient and hygienic discharge overside or to an enclosed tank with a suction pipe served by a mechanically operated pump provided that a wash-basin shall not be required to be fitted in a sleeping room for petty officers if washing accommodation is readily accessible from the sleeping room.