Ka Wai Ola. “Water for life.”

The sweet fresh water that Oahu has provided residents for centuries is the bounty of our island’s amazing mix of natural features.

The island’s mountains are just the right height to tease water from passing clouds.

Each year over 1 billion gallons of rain fall on those mountains. About one-third of the rainfall percolates into aquifers — underground porous rock that acts like a sponge and retains water. Another third returns to the water cycle through evaporation, and the final third fills surface streams and ponds, nourishing the island’s watersheds.

A unique feature of the island’s geology that ensures the purity of our water, is the porousness of the lava rock. It acts as a natural filter providing the residents of Oahu with some of the world’s best drinking water.

Hawaiians worked and lived in land divisions called ahupua‘a that were formed around these watersheds and allowed them to manage and use the water within each of these areas. Today’s generation depends upon modern infrastructure and processes to get water from Oahu’s aquifers to wherever people live. Serving as a constant steward of Oahu’s water supply, the City and County of Honolulu Board of Water Supply (BWS) provides about 145 million gallons of drinking water every day to about 1 million people, charging them less than a penny per gallon.

The BWS water system is one of the largest in the nation, with 2,100 miles of pipe, some as large as 42 inches in diameter; 386 pumps; 212 water sources; and 171 water storage reservoirs. This vast system has been developed and expanded over a period of 100 years, with a replacement value of nearly $16 billion. The people of Oahu have made a sizable investment in this critical public water system. We continue this investment today, mindful of our own quality of life and that of future generations.

Like any infrastructure system, particularly those that are sizable with complex moving parts, Oahu’s water system has its challenges, including the wear-and-tear of constant use and aging. Our community experiences this most dramatically in water main breaks, which have been occurring more frequently.

With this in mind, BWS has prepared a long-term water master plan that provides extensive data, detailed assessments, computer modeling and projections that make it possible to make critical decisions about Oahu’s water system for now and for decades to come. To put the master plan into action, BWS developed a 30-year capital improvement program that provides an analysis-based, multidecade strategy for prioritizing when specific water infrastructure projects should be implemented, accounting for risk, feasibility and projected costs.

To assure sufficient funding for implementation, BWS has completed a long-range financial plan that will guide how to implement system repairs and replacement, as well as accommodate growth, while keeping water rates affordable.

The BWS board of directors recently approved a new 5-year rates and fees schedule that will introduce new tiers as well as incremental rate increases over this period. This includes a lower, essential-needs tier and rate to address affordability for residential customers with low water use. A new approach to monthly billing charges based on meter size is another significant change.

This long-term look is the best approach to sustain, expand, repair and replace critical water infrastructure to support Ka Wai Ola for the people of Oahu. This forward-focused planning will guide our policy makers, managers and technical staff on how to successfully sustain our water system and assure fresh water for generations now and into the future.

Ernest Y.W. Lau is manager and chief engineer of the Honolulu Board of Water Supply.