Smithtown drain cleaning costs vary depending on the severity of the clog. However, the average cost of clearing a tub, sink or bathroom drain is around $100 to $200. A clog from the laundry drain can cost between $150 to $215 and a remedy for a toilet clog costs $100 to $270. All these include a $50 service fee. A cleaning service for a main pipe clog can cost $180 for an exterior clean out, $270 to clear it through a drain vent and approximately $400 if the toilet has to be pulled and drain cleaning equipment will be required.