Home Additions in Morgan Hill, CA
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Hillside Lots and Design Permits
Morgan Hill’s Hillside Combining District applies to land with slopes of 20% or more, and any property with a slope of 10% or more is treated as a hillside property. Additions there may require a Design Permit and a geotechnical survey. Sites with natural features can also need a discretionary Design Review Permit. We check slope and zoning before design.
Addition Work
Trees, Historic Homes and Stormwater
- Trees (Municipal Code 12.32): oaks, California bays, madrones, sycamores and alders are protected. “Significant” trees are natives 6 inches or more in diameter and non-natives 13 inches or more. Pruning more than 25% of the canopy needs a permit.
- Historic: exterior changes to designated or significant historic resources need a Historical Alteration Permit; demolition needs Planning Commission approval.
- Septic: properties more than 300 feet from a City sewer line involve County Environmental Health.
Stormwater: Morgan Hill is regulated by the Central Coast Regional Water Quality Control Board. Projects that create or replace 2,500 sq ft or more of impervious area, including single-family homes, must use low-impact development site design measures. Detached single-family homes face treatment and retention requirements at 15,000 sq ft, and all projects need peak-flow control at 22,500 sq ft. A Stormwater Worksheet is part of the submittal.
Permits
Planning, Building & Fire Prevention, Engineering
17575 Peak Avenue, Morgan Hill, CA 95037 · (408) 778-6480
Monday to Friday, 8 a.m. to 5 p.m. (Building counter closed noon to 1). pe*****@***********ca.gov · pl******@***********ca.gov
Inspections are scheduled through eTRAKiT; Fire Marshal inspections run Tuesday to Friday.
Fire: Morgan Hill has its own fire department, reconstituted in 2013 and staffed by CAL FIRE under an agreement. Fire sprinkler permits are submitted by PDF email. Updated fire hazard severity zone maps added new High zones in 2025, where 100 feet of defensible space and wildfire building codes apply.
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Other Morgan Hill services: ADUs · Bathrooms · Kitchens · New Homes · Morgan Hill overview
Same service nearby: San Martin · Gilroy · San Jose
See home additions and second stories.
Morgan Hill Home Additions FAQ
Is my Morgan Hill lot a hillside property?
Any property with a slope of 10% or more is treated as hillside; the Hillside Combining District applies at 20% or more.
Do stormwater rules apply to my addition?
Projects creating or replacing 2,500 sq ft or more of impervious area must use low-impact development measures.
Are oak trees protected?
Yes. Native oaks 6 inches or more in diameter are significant trees.
Who issues the permit?
The City of Morgan Hill Building Division.