Sewage Cleanup in Honolulu, HI

Honolulu's sewage cleanup market is driven by the extraordinary I&I surges that the city's sanitary sewer system experiences during Ko'olau Mountain storm events — rainfall events that can deposit 10 to 20 inches in a single storm and that saturate soils around aging sewer laterals throughout the urban watershed to depths that generate groundwater infiltration rates 500 to 1,000 percent above normal for extended periods. The City and County of Honolulu's Board of Water Supply and Department of Environmental Services manages a sewer system that includes aging vitrified clay pipe in the older neighborhoods of Manoa, Nu'uanu, and Punchbowl — areas where the original colonial-era infrastructure has been extended and patched rather than replaced, creating numerous I&I entry points. Honolulu has been subject to Clean Water Act enforcement actions for sewage overflows into state waters, including the 2006 Ala Wai Canal sewage spill — Hawaii's largest environmental disaster, in which 48 million gallons of sewage overflowed into the Ala Wai Canal and subsequently into the Pacific Ocean at Waikiki Beach after heavy Ko'olau rains overwhelmed lift station capacity. Sewage cleanup in Honolulu condominium and apartment buildings — where the majority of the population resides — is complicated by the high occupancy density, the shared plumbing systems between floors, and the requirement to temporarily relocate residents from contaminated units during cleanup, a relocation that in Honolulu's tight rental market can be difficult to accomplish.