40 City Mayors Set Data Center Rules For Grids And Water

Cities Put Data Centers Into Planning Rules

Mayors from 40 of the world's largest cities have agreed to coordinate rules for data center growth, putting AI infrastructure inside urban planning debates over power, water and local communities.

The Global Pact for Urban Data Centers emerged during London Climate Action Week.

It is intended to guide permitting and planning decisions, as well as negotiations with data center companies and governments.

London, Phoenix and Melbourne are expected to be among the cities covered by the framework.

The pact does not create a single global permitting code.

The rules are expected to be adapted to local conditions, which means the impact will depend on how each city turns the framework into land-use, energy, water and cost-sharing decisions.

Grid Pressure Drives The Pact

Melbourne Lord Mayor Nicholas Reece compared data center pressure on the electricity grid to the arrival of air conditioning in the 1950s, but said the current buildout is happening over only a few years.

That comparison puts data centers in the same category as major urban infrastructure loads, not only technology real estate.

Phoenix gives the pact a concrete demand marker.

Mayor Kate Gallego said Phoenix and the surrounding area have 225 existing or planned data centers, and that the sector could nearly double the city's electricity demand.

Those figures explain why city governments are moving into a role that used to sit mainly with utilities, hyperscalers and developers.

Data centers increasingly affect substations, transmission upgrades, water planning, zoning and neighborhood concerns.

Four Pillars Target Land, Metrics And Costs

The pact has four pillars.

Cities will prioritize brownfield regeneration and adaptive reuse, avoid displacement, and site facilities with local government input to reduce public-health burdens.

The framework also calls for measurable benchmark data on sustainability and public-health metrics.

For energy, it says demand should be met without building new fossil fuel plants, extending existing plants or reopening decommissioned plants.

Cost allocation is another key element.

The pact says companies should directly fund necessary upgrades to energy, water and network infrastructure, with fair-share pricing tied to sustainability performance.

C40 Coordination Gives The Framework A Channel

C40 Cities will coordinate the pact.

The network includes nearly 100 large cities working together on climate action, giving the framework a route for sharing standards even if each city adapts the rules locally.

The public description says the full city list is available separately, so the current reporting does not identify every municipality that will apply the framework.

London Mayor Sadiq Khan said AI and data centers can play a major role in future urban prosperity, while residents should expect growth to be managed responsibly.

That position captures the trade-off facing mayors: cities want digital infrastructure investment, but not at the cost of unpriced grid upgrades or unmanaged water pressure.

For data center operators, the pact points to a more demanding approval environment in major cities.

The concrete burden is whether developers can show brownfield siting, public metrics and direct funding for energy, water and network upgrades before local permitting decisions are made.