To use drain out bathroom in a regular household drain, simply remove the standing water from the drain and pour half a bottle of drain out bathroom in the drain allow product to work for minutes, then flush drain with warm water. Thank you so much for assigning a positive, knowledgeable, and efficient technician for our furnace time-up! he represents everything we love and have grown to expect from holt! For enquiries, please e-mail to. Do plumbers offer a written warranty? Boiler service completed.