They can! We've got a nuclear power plant that evaporates water from sewage for cooling.

https://en.wikipedia.org/wiki/Palo_Verde_Nuclear_Generating_Station

The Palo Verde Generating Station is a nuclear power plant located near Tonopah, Arizona[5] about 45 miles (72 km) west of downtown Phoenix. Palo Verde generates the most electricity of any power plant in the United States per year, and is the largest power plant by net generation as of 2021.[6] Palo Verde has the third-highest rated capacity of any U.S power plant. It is a critical asset to the Southwest, generating approximately 32 million megawatt-hours annually.

At its location in the Arizona desert, Palo Verde is the only nuclear generating facility in the world that is not located adjacent to a large body of above-ground water. The facility evaporates water from the treated sewage of several nearby municipalities to meet its cooling needs. Up to 26 billion US gallons (~100,000,000 m³) of treated water are evaporated each year.[12][13] This water represents about 25% of the annual overdraft of the Arizona Department of Water Resources Phoenix Active Management Area.[14] At the nuclear plant site, the wastewater is further treated and stored in an 85-acre (34 ha) reservoir and a 45-acre (18 ha) reservoir for use in the plant's wet cooling towers.

If you're location-agnostic as to your datacenter, though, probably easier to just stick a datacenter by the ocean and use seawater, though. Lots of that.

EDIT: Or make use of the waste heat instead of throwing it away. If it's winter and you're a town in Alaska, say, you'd probably just as soon have the heat piped your way.