Abstract: A method for sealing a drain by pouring a chemical sealant comprising ethylene oxide/propylene oxide block co-polymer into the drain trap in a sufficient quantity to displace any existing fluid in the drain with the sealant and allowing the sealant to remain in the drain trap. The sealant will not evaporate (significantly if at all), and will provide a seal, for a period of at least twelve months. The sealant may be removed and the drain opened by flushing with water.