Sewage stabilization ponds are rapidly gaining acceptance in this country as a proven means of municipal waste treatment. Histories of the use of stabilization ponds to treat sewage have appeared in several articles. Heretofore, most of the performance records of sewage ponds have referred to areas of moderate rainfall, high evaporation and solar radiation as exemplified by studies of ponds in North Dakota. The newly constructed sewage stabilization pond at Long Beach, Washington, afforded an excellent opportunity for study of performance in a maritime climate.