Section 3 Working Paper 3: Planning Tools, Compatibility, and Projects in Process

Draft for committee and County Counsel review | September 18, 2026

Recommended regulatory architecture

Use more than one tool. A countywide ordinance should define and regulate the use; a suitability overlay should identify preferred areas; a CUP should test site-specific impacts; and a specific plan or development agreement should be reserved for a campus whose size or infrastructure demands exceed conventional zoning.

The County’s own Land Use Element supports specific plans where conventional zoning is inadequate for a large industrial park or area needing further study. It also requires the plan to address the location and intensity of water, sewer, drainage, energy and other facilities and to demonstrate public benefit.

Compatibility: use buffers plus performance standards

A fixed setback alone cannot manage low-frequency fan noise, nighttime testing, exhaust, plume behavior or cumulative generator operation. A pure performance standard can also fail if it lets a project place industrial machinery against a home and promise later mitigation. Use both.

Recommended study standards, not final legal numbers

1. Residential, schools, hospitals and care facilities: require discretionary review whenever a data-center building, substation, cooling plant, BESS or generator yard lies within a defined study radius. Establish final distances only after acoustic/air/fire analysis. As a starting policy direction, keep generator yards and major substations out of direct adjacency and require a larger buffer than for the enclosed server building.
2. Noise: retain Title 9’s receiving-zone limits, but add data-center methods: pre-project ambient baseline; octave-band and low-frequency analysis; tonal and impulsive penalties; normal, full-cooling, generator-test and credible emergency modes; measurement at the receiving property and inside the nearest sensitive receptor where warranted; post-opening verification.
3. Generators: distinguish emergency outage operation from commissioning, testing and demand-response/routine generation. Cap and report non-emergency hours; require synchronized-test analysis rather than one-engine assumptions; locate fuel and exhaust away from sensitive receptors.
4. Air and environmental justice: require cumulative analysis of diesel/gas engines, construction, truck trips and nearby industrial sources. Give special attention to communities already bearing high pollution loads. Do not assume “emergency” equipment has no operating impact.
5. Water and heat: require annual and peak-day demand, cooling mode, cycles of concentration, blowdown destination, fire flow and drought/emergency plan. Air or closed-loop cooling should receive a preference, not an automatic pass, because energy and heat effects remain.
6. Agriculture: avoid fragmenting productive farmland, impairing drains/canals, creating incompatible glare/noise, or using an agricultural zone merely because acreage is cheap.
7. Airport, flood, habitat and seismic constraints: map these as exclusions or conditional layers before identifying a preferred site.
8. Building and site design: screen mechanical equipment; control lighting at property lines; place noisy plant at the interior; preserve emergency access; require landscape/buffer survival standards suited to desert conditions.

How to handle projects already in process

There is no single “grandfathered” category. County Counsel should create a project-by-project entitlement table.

Questions for each project

• What applications have been submitted, and were they deemed complete?
• What permits, maps, zone changes, specific plans or development agreements were actually approved?
• Was any tentative map expressly a vesting tentative map?
• Has a building permit been issued, and has the developer performed substantial work and incurred substantial liabilities in good-faith reliance on it?
• What precise use, capacity, phase and parcel does any claimed right cover?
• What approvals remain discretionary?
• Which building, fire, health, nuisance and operating requirements remain applicable?

Legal reference points

• California’s traditional vested-right rule is narrow. Avco addresses the conflict between reliance on approvals and later regulation; the common shorthand is a valid building permit plus substantial work and liabilities in reliance, but County Counsel must apply the actual facts.
• A vesting tentative map can confer rights to proceed in substantial compliance with specified ordinances, policies and standards. Gov. Code §66498.1.
• A development agreement can lock in rules governing permitted uses, density, design and construction unless the agreement provides otherwise. Gov. Code §§65864-65866.
• CEQA applies to discretionary approvals including zoning amendments, variances, CUPs and tentative maps unless exempt. Pub. Resources Code §21080.
• An urgency interim ordinance is authorized under Gov. Code §65858 when the required health, safety and welfare findings and procedures are met. Its use, duration and effect on pending matters require County Counsel review.

Transition recommendation

1. Apply new rules prospectively to new applications.
2. Apply them to pending applications to the extent legally allowed, based on the entitlement table rather than a blanket label.
3. Honor a demonstrated vested right only to its documented scope.
4. Preserve generally applicable building, fire, health, nuisance and operating authority where the law allows.
5. Offer a defined transition process: applicant submits its claimed vesting instruments; County Counsel issues a written scope determination; staff identifies which new standards remain applicable.
6. Do not let a lot merger, pre-application discussion, feasibility study or utility inquiry stand in for a land-use entitlement.

Sources

• Imperial County Land Use Element: https://www.icpds.com/assets/planning/land-use-element/land-use-element-2015.pdf
• Title 9 zoning provisions: https://www.icpds.com/assets/5-Zoning-Areas-Established-.pdf
• Title 9 noise: https://www.icpds.com/assets/planning/ordinances/title-9-div-7-2015.pdf
• California CEQA applicability, PRC §21080: https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=PRC&sectionNum=21080
• Interim zoning, Gov. Code §65858: https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=GOV&sectionNum=65858
• Development agreements, Gov. Code §§65864-65866: https://leginfo.legislature.ca.gov/faces/codes_displayText.xhtml?article=2.5.&chapter=4.&division=1.&lawCode=GOV&title=7.
• Vesting tentative maps, Gov. Code §66498.1: https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=GOV&sectionNum=66498.1.
• Avco: https://scocal.stanford.edu/opinion/avco-community-developers-inc-v-south-coast-regional-com-27961
• Loudoun County official standards project: https://www.loudoun.gov/datacenterstandards
• Loudoun data-center ordinance: https://online.encodeplus.com/regs/loudouncounty-va-zo/doc-viewer.aspx?secid=859
• Prince William County overlay example: https://princewilliamcounty.elaws.us/code/coor_ch32_artv_pt509_sec32-509.02
• Fairfax County 2024 amendment example: https://www.fairfaxcounty.gov/planning-development/sites/planning-development/files/Assets/Documents/zoning%20ordinance/adopted%20amendments/ZO_112_1-2024-9.pdf

Legal caveat: This is a policy research paper, not a legal opinion. County Counsel should determine the effect of any existing approval or claimed vested right and review all transition language.