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Watering Slopes and Fuel Mod Zones

CAnativeplantshillsideUnder Level 4 water restrictions conventional spray sprinklers will no longer be permitted after July 31st and will either need to be converted to a low-volume drip system, capped, or turned off. There are three exceptions which allow for continued use of traditional spray sprinklers: 1) active playing fields and recreation areas in public parks, schools, licensed daycare and golf courses, 2) irrigation of vegetation on steep slopes to prevent soil erosion and, 3) fuel modification zones when required in the development conditions of approval. For all other residential settings low-volume drip systems must be used. Let us look at two of these exceptions in more detail: slopes and fuel modification zones.

What qualifies as a slope?

There are two main types of slopes—natural slopes and man-made “engineered” slopes. We are fortunate to live in a City that includes many natural rolling hills. If natural hillsides are left in their natural state and not planted, they do not require watering. However, in some cases, people have planted these slopes with ground cover and other vegetation and installed irrigation systems to water them. In other cases, cuts and fill slopes were made in the natural landscape to grade land for housing and commercial property development purposes. This cut and fill grading work created new slopes, some of which are steeper than the natural terrain, and as such vegetation and groundcover is often used to reduce the possibility of erosion or instability on these man-made or “engineered” slopes.

It may be impractical for property owners to irrigate ground cover or vegetation on steep or extensive slopes with a drip system. Thus an exemption to the low-flow drip system requirements are made for irrigating existing ground cover or other non-turf vegetation planted and essential to maintain slope stability on slopes of at least 6 feet in height and exceeding 20% grade, or by City Engineer’s approval. Irrigation for this purpose is also allowed an additional day of watering (Wednesday). These allowances are made regardless of whether the slope is natural or engineered.

What is a fuel modification zone? I live next to Open Space. Can I water an extra day for fire protection?

Fuel modification zones, otherwise known as “Fire Breaks” are typically located behind residential backyards and commercial properties, and are areas where vegetation is significantly thinned or kept very low to reduce the amount of potential fuel for wildfires.  Backyard landscaping is generally not considered a fuel modification zone. The City’s watering restrictions state that “Fuel Modification Zones as required in development conditions of approval for fire protection are allowed an extra day of irrigation to mitigate fire risks and are not required to use low volume irrigation systems unless otherwise conditioned or required by law or agreement." Irrigated fuel modification zones are often 100’ in depth, and usually maintained by HOAs (or POAs) as part of the original development conditions with the City. Your HOA should be familiar with their requirements to maintain these areas. This provision in the City’s water restrictions allows HOAs and POAs an additional day (Wednesday) of watering to keep plantings in these fuel modification zone areas alive. However, many of these fuel modification zones are no longer irrigated and are just cleared with no plantings and thus require no irrigation.

If you are concerned about fire safety, the Ventura County Fire Dept’s Ready-Set-Go pamphlet discusses landscaping and other topics and is accessible at this link: Please refer to the guidelines for creating defensible space. including the need to remove dead or dying vegetation from your property. 

I received an Annual Brush Clearance Notice from the Fire Department. Does that mean my property has a fuel modification zone?

No. The Fire Department sends out a “Notice to Abate Fire Hazard” to hundreds of properties in the City annually. This notice is a notification that the property must be cleared of seasonal and recurrent weeds, stubble, brush, dry grass, dry leaves, tumble weeds, rubbish, litter or other flammable materials of any kind to remove potential fire hazards. Generally, fire hazards must be removed within 100 ft of structures. This notice does not require you to irrigate a fuel modification zone but rather to clear your property of dry and dead brush per VCFD's determination. A VCFD required clearance area is not equivalent to a Fuel Modification Zone that was established as part of City tract development conditions.

Watering day, time and length

Regardless of the type of irrigation system you are using, watering can only occur on the assigned watering day (Saturday or Sunday, plus Wednesday for certain permitted uses), and must NOT occur between 8 am and 6 pm. Traditional spray sprinklers are also subject to a limit of 15 minutes watering per irrigation zone. Drip irrigation is not subject to the 15-minute time limit.

More information or questions?

If you are unsure whether your slope qualifies for extra watering due to erosion potential, or if you think you may have a fuel mod zone within your property that you are required to irrigate, contact For more information about these and other water restrictions visit

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