High sudsing detergents used in clothes washers produce suds that tend to disrupt the venting action of the venting systems and can also spread through the lower portions of a multi-storey drainage system. The more turbulence, the greater the suds.
One solution that avoids the creation of suds pressure zones involves connecting the suds-producing stack downstream of all other stacks and increasing the size of the horizontal building drain to achieve a greater flow of air and water. Using streamlined fittings, such as wyes, tends to reduce suds formation. Check valves or backwater valves in fixture outlet pipes have also been used to correct problem installations.
