The above-ground pipework is referred to as sanitary pipework; the underground pipework is referred to as foul drains and foul sewers.
Cyfeirir at y systemau o gwteri a phibelli dŵr glaw uwchben y ddaear fel draenio toeau; cyfeirir at y pibelli o dan y ddaear fel draeniau dŵr wyneb a charthffosiaeth dŵr wyneb.