💧 Will a data center drain our water supply?

This is one of the most common and reasonable questions, because some data centers use water for cooling. A few key facts:

• Not all data centers use much water. Cooling approaches range from water-intensive evaporative cooling to closed-loop and air-cooled systems that use very little water. The design matters enormously.
• The City can make water use a condition of approval. Through the overlay’s review, we can require an applicant to disclose expected water use and can favor or require low-water cooling designs.

Is the industry actually using less water — and adapting to local conditions?

Yes — and this is the part that often gets left out. Water use is driven by the cooling design, and the industry is moving toward designs that use far less water, including choosing low-water cooling specifically in places where water is scarce. Concrete, recent examples:

• Closed-loop and “zero-water” designs. Microsoft announced in December 2024 that all of its new datacenter designs (since August 2024) use a closed-loop, chip-level cooling system that is filled once and recirculated — using essentially zero water for cooling and avoiding more than 125 million liters of water per year, per datacenter.
• Matching cooling to the climate / water availability. Amazon Web Services uses free-air cooling instead of water when temperatures allow — in its Ireland and Sweden regions it uses no water for cooling about 95% of the year — and switching to recycled (non-drinking) water cut water use at its Santa Clara site by 85%. Google likewise says it looks for air-cooling or recycled water in locations with high water risk.
• Water-stewardship commitments. AWS and Google have both committed to be “water positive” by 2030 (returning/replenishing more water than they use), and to expand the use of recycled and reclaimed water.

An honest caveat: several of these are recent or forward-looking corporate commitments, and industry-wide water use is still large and growing as AI expands (see the LBNL and EESI sources below). The point is not that every data center is low-water today — it’s that low-water cooling exists, is proven, and can be required. That is exactly why the City intends to make cooling technology a condition of review.

What the City can require / commit to:

• Disclosure of projected annual water use before approval.
• Preference for closed-loop or air-cooled designs in water-sensitive cases.
• Confirmation from the water provider that capacity exists without harming residential service.

Specifics such as the water provider serving the overlay area, the available capacity, and any commitments will be confirmed as part of the review of any actual project. Under Section 13 and the proposed Section 13A, an applicant must submit a water-demand analysis and disclose its cooling technology, and a project may not materially impair water availability or raise water costs for residents. These are intended to be enforceable conditions of approval, not promises.