Fire & Drought · Story
Defensible Space and Water Around a Paso Robles Ranch House
Defensible space in the Paso Robles hills means 100 feet of managed vegetation under state law, plus hoses and stored water that firefighters can actually use.
By the Ranch House Water desk · Updated · 6 min read
On the oak and grass ranchettes outside Paso Robles, fire season is long and dry. NOAA's 1991-2020 normals for the station in town put the average July high at 90.5°F, with about 21 days a year at or above 100°F, and nearly all the rain falls between December and March. State law answers that with a cleared, managed ring of land around every house in the State Responsibility Area.
What does state law require around the house?
It requires 100 feet of defensible space on each side of the structure, but not past your property line. Public Resources Code 4291, as amended effective October 13, 2025, calls for heavier fuel reduction between 5 and 30 feet from the house and an ember-resistant zone within 5 feet, both shaped by Board of Forestry regulations.
The same section lists two chores that are easy to miss. Any part of a tree within 10 feet of a chimney or stovepipe outlet must be cut back, and the roof must be kept free of leaves, needles and other plant litter. CAL FIRE's defensible space page describes the two outer zones, which run out to 100 feet, as required by law.
- Ember-resistant zone (Zone 0)5 feet
- Tree clearance from a chimney outlet10 feet
- Outer edge of heavier fuel reduction30 feet
- Full defensible space100 feet
Source: Public Resources Code 4291
Is Zone 0 the law yet?
Not as of late October 2026. The Board of Forestry's Zone 0 page, in an archived copy from October 21, 2026, lists the board's August 19, 2026 decision and says the rule package is still in final review with the Office of Administrative Law. CAL FIRE's own consumer page puts it plainly: Zone 0 is not legally required yet, though it matters for ember defense.
When it does take effect, PRC 4291 starts the clock for new homes first and gives existing homes three more years after that date. No start date had been published when this page was last updated. The law also says the board's accompanying document must address things that are not plants, such as woodpiles, propane tanks, decks, patio furniture, barbecues and fire pits, and an attached deck counts as part of the house for the 5-foot zone.
What about propane tanks and outbuildings?
For sheds, barns and LPG tanks, CAL FIRE's defensible space page wants a 10-foot apron scraped to mineral soil, then another 10 feet kept free of anything that burns. Where a tank sits near dry grass at the edge of a yard, that 20-foot ring is worth marking out each spring.
Clearance is a fire-season chore, not a leak response. If you ever smell gas or propane, indoors or out, leave the area first, keep away from switches, phones and anything that could spark, and once you are outside or at a neighbor's, phone 911 and then the company that fills your tank. Do not go looking for the leak. Our story on propane smells on rural property explains why.
How should water be set up before fire season?
Set it up so it works without you. CAL FIRE's home hardening page suggests long garden hoses that reach all areas, including roofs and decks, and mentions pumps for pools or wells as extra water sources.
On a private well, that advice runs into a plain fact: an electric pump stops when the power does, and power shutoffs often come with exactly the wind that drives fires. Our story on power shutoffs and wells covers what that means for water at the house. New homes in the county also carry a dedicated fire reserve and a roadside connection for engines, explained in fire water storage.
What should be done with water when it is time to leave?
Leave when you are told to, and do only the steps time allows. CAL FIRE's evacuation checklist suggests attaching garden hoses to outside taps for firefighters, filling buckets and setting them around, and keeping a ladder handy so firefighters can reach the roof.
The same checklist warns against leaving sprinklers or water running, because it can drop the water pressure firefighters need. On a property where a well pump and storage tank are the only supply, running sprinklers can also drain the tank that crews might draw from.
Who inspects, and who can help?
CAL FIRE and SLO County Fire carry out defensible space inspections in the State Responsibility Area and can explain what a 100-foot ring looks like on a sloped or oak-covered lot. For household water during fire season, also see our section on fire and drought and the story on water storage tanks.
Where to call
- CAL FIRE's San Luis Obispo Unit, which also serves as County Fire — defensible space questions, inspections and fire water on your parcel. Fire Marshal page
- California Board of Forestry and Fire Protection — status of the Zone 0 rules. Zone 0 rulemaking
- CAL FIRE Ready for Wildfire — defensible space, home hardening and evacuation steps. Ready for Wildfire
- ReadySLO — current county emergency information. ReadySLO
Common questions
Do I have to clear past my property line?
No. PRC 4291 requires 100 feet from each side of the structure but not beyond the property line. Where your neighbor's land falls inside that ring, CAL FIRE or SLO County Fire can explain your options.
Do I need to remove everything within 5 feet of the house now?
Not by law yet. Zone 0 rules were adopted by the Board of Forestry in August 2026 but were still in state review in late October 2026. CAL FIRE still recommends heavy fuel reduction there for ember defense.
How much clear space does a propane tank need?
Twenty feet in all: the first 10 feet cleared down to bare dirt, the next 10 kept clear of flammable plants, per CAL FIRE. If you ever smell propane, leave the area first and make the calls to 911 and the propane company from outside.
Should I leave the sprinklers on when I evacuate?
No. CAL FIRE says running sprinklers or water can lower the water pressure firefighters need. Attach hoses to outside taps for crews instead, if there is time.
Does a tree near the chimney need trimming?
Yes. PRC 4291 says any part of a tree within 10 feet of a chimney or stovepipe outlet must be removed.
Sources
- California Public Resources Code §4291 (archived copy, May 8, 2026) — 100 feet, 5 and 30 foot zones, chimney and roof duties, Zone 0 timing
- Board of Forestry — Defensible Space Zones 0, 1, and 2 (archived copy, Oct. 21, 2026) — August 19, 2026 decision; review pending
- CAL FIRE Ready for Wildfire — Defensible Space — zones, LPG tank and outbuilding clearance
- CAL FIRE Ready for Wildfire — Hardening Your Home — hoses and pumps for pools or wells
- CAL FIRE Ready for Wildfire — evacuation checklist — hoses for firefighters, buckets, sprinklers off, ladder
- NOAA NCEI — 1991-2020 normals, Paso Robles in-town station — July highs and days at or above 100°F
- PG&E — Gas Safety — leave the area and call 911 if you smell gas