Sludge facilities for municipal wastewater plants are usually designed for average expected load, not peak load. Sludge peak loads, however, are very significant at the 125-mgd West Point plant in Seattle, Washington. Records are presented to demonstrate the magnitude of these peaks and their implications for design. The peaks are not fully understood but two external sources are known to exist. First, solids deposit in the sewers during dry weather and are washed out during storms. Second, solids from storm inflow are substantial. In-plant sludge recirculation is also significant.