We recommend the following steps be taken to ensure that transmission through the wastewater plumbing system is minimised: (1) do not ignore unexplained foul smells in bathrooms, kitchens, or wash areas; (2) make sure that all water appliances in bathrooms and kitchens are fitted with a functioning U-bend; (3) to prevent the loss of the water trap seal within a U-bend, open a tap on all water appliances for at least 5 s twice a day (morning and evening) paying special attention to floor drains in bathrooms and wet rooms; (4) if the wastewater pipework from an appliance appears to be disconnected or open, seal it immediately (ie, use an elastic rubber glove to cover the end; a plastic bag and some tape will suffice, ensuring the bag has no holes); (5) if there appears to be any crack or leak in pipework, seal with tape or glue; and (6) continuously monitor whole system performance (for large or tall buildings).