The Hillsboro Water Department has heard from many community members regarding data centers in Hillsboro, including questions about how these facilities use water, what that means for our local supply, and how the City is managing this demand responsibly. This FAQ is compiled from seven recent Public Records Requests. It is meant to help community members better understand the relationship between data center operations and our shared water resources, and what Hillsboro Water is doing to ensure a reliable, sustainable water future for everyone in the community. 

Are data centers using most of Hillsboro’s water?

No, based on 2025 data, data centers receive about 1.76% of Hillsboro’s total water demand. Hillsboro used about 6.3 Billion Gallons (BG) in 2025, with 3.2 BG used in total industrial processes. About 111 million gallons (MG) were used at data centers, or about 3.4% of total industrial demand. 

For reference, the combined 2025 water usage of all Hillsboro data centers (~14 sites) does not even exceed the water usage for a solar panel producing company that operated in Hillsboro during the 2000/2010’s and has since gone out of business. That one industrial site used about 150 MG per year, compared to the 111 MG used by the 14 data center sites referenced above. Hillsboro currently has a treatment capacity of 41.7 Million Gallons per Day (MGD) but only peaks (highest usage day in a year) at around 30 MGD, so there is room for growth in all customer classes.

Do data centers pay less for water than residential customers?

No, data centers are classed as either commercial or industrial, which both pay higher base (fixed) and usage rates than typical residential customers. 

Would more data centers in Hillsboro increase residential water rates?

No, water rates are designed so that all customers, including residential, commercial, and industrial users, pay their fair share based on how they use the City’s water system and how much water they use. 

Cost-of-Service studies are conducted about every five to six years to ensure that each of the customer classes are paying their fair share, so residential rates will not rise due to an increase of data centers. 

Residential meters (5/8”) pay a $21.94 monthly fixed charge and most customers’ water use falls in first-tier rate of $3.99 per ccf (748 gallons) up to 4 ccf, or the second-tier rate of $4.58 per ccf up to 8 ccf. Industrial users like data centers pay a $512.16/month fixed charge for a 2” meter and pay $5.17 per ccf (748 gallons) for usage.

Is the Willamette Water Supply System (WWSS) being specifically built to serve data centers?

No, the WWSS is being built to serve the future needs of all customers in Hillsboro and the region, not specifically data centers. The new water supply won’t reach north Hillsboro’s industrial area until at least the mid-2030’s, as that part of the pipeline was deferred to minimize rate impacts due to rising project costs.

Plans for a secondary water supply for Hillsboro began 30 years ago, before data centers were even a consideration. Hillsboro last added to its water supplies in the 1990’s, with the expansion of Barney Reservoir, and since then the city has continued to grow. That growth is seen across all customer classes, not just in the industrial/commercial classes, which include data centers. The new water treatment will have an initial capacity of 60 MGD, with Hillsboro receiving 15 MGD.

What is the purpose of the WWSS – if not for data centers?

The focus of the WWSS is to bring resiliency and redundancy to Hillsboro’s water supply. As stated above, additional water will allow for growth in all classes - including industrial and commercial sectors, schools and public facilities, and residential areas like South Hillsboro. Currently, Hillsboro only has one water source – the Joint Water Commission. If anything happens to that source, Hillsboro does not have another option to fall back on - unlike other water providers in the area such as Forest Grove, Beaverton and Portland. The WWSS will provide a second reliable source for all Hillsboro customers. 

Additionally, the WWSS is being built to withstand the potential Cascadia Subduction Zone Earthquake, so water recovery time after a major disaster will be much less than most other water systems in the Pacific Northwest – for all customers. Water system resiliency protects public health, provides fire suppression, and delivers water fit for human consumption in a major seismic event.

Where do data centers dispose of wastewater?

Hillsboro is committed to environmental compliance and stewardship of our natural resources.

All wastewater in the City of Hillsboro goes to the sanitary sewer system for treatment, and the City does not discharge to groundwater. Clean Water Services (CWS) provides sewer treatment services for the City of Hillsboro. CWS has extensive environmental regulatory requirements in their discharge permits to meet standards set by the Clean Water Act. They use state-of-the-art treatment facilities to clean wastewater to some of the highest standards in the nation before water is returned to the Tualatin River. 

Is Hillsboro's drinking water affected by Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS)? 

No. PFAS compounds have never been detected in Hillsboro's water supply. 

The Tualatin River, Hillsboro's current source water, has shown no detections. These compounds are far less prevalent in Oregon than in other parts of the country. Hillsboro Water tests for all six PFAS compounds regulated by the EPA, and as part of the EPA's Unregulated Contaminant Monitoring Rule 5 (UCMR 5), also tested for 29 additional unregulated PFAS. None were detected.

Hillsboro's future additional water source, the Willamette River, has also shown no detections for PFAS at the river intake where water is drawn for treatment. When the Willamette Water Supply System (WWSS) comes online, the new treatment plant will utilize an advanced multi-barrier treatment approach — including granular activated carbon (GAC), ozone, and UV — to effectively remove PFAS. This design exceeds Safe Drinking Water Act requirements and is built to address emerging contaminants before they are formally regulated by the EPA.