Tax Calculation

The tax will be calculated for each Parcel based upon the Parcel’s Impermeable Area as determined by the County Landcover Survey or other applicable tool. The boundaries of the area, identification of the Parcels subject to the tax, and the method for calculating the tax for each Parcel is established by the ordinance incorporated by the Los Angeles County Flood Control District Code. The rate used for calculating the tax, as established by the ordinance, will remain the same from year to year. The Chief Engineer may periodically re-evaluate the characteristics of Parcels to ensure accuracy of tax calculations.

The Board of Supervisors will periodically initiate an update to the County Landcover Survey which is used to determine the Impermeable Area for each Parcel throughout the District.

For more information see Section IX of Enclosure E in the Board Letter.

To look up your parcel tax, please visit our Tax Lookup and Appeals Tool.


The special parcel tax provides two options for exemption:

Low-Income Seniors

  • Parcels owned by qualifying low-income seniors
  • Parcels exempt from ad valorem property taxes

Low-income senior property owners may apply for an exemption from this special parcel tax. The applicant must be both a senior property owner (62 years of age or older, residing in a Single-Family Residence) and low-income, as determined annually by the California Department of Housing and Community Development.

The low-income senior exemption application and instructions are expected to be available in mid-September 2019.

Ad Valorem-Exempt Properties

Parcels that are exempt from ad valorem property taxes are also exempt from this special parcel tax. This includes qualifying non-profit organizations and other exempt properties. This exemption will be automatically applied to the tax bill with no action required of the property owner.


A credit program will be available for property owners who demonstrate stormwater improvements that result in water quality benefits, water supply benefits, and community enhancement benefits.

The credit program application process, qualifying improvements, and verification requirements are expected to be available in mid-September 2019.


Property owners who believe their tax has been calculated incorrectly can file an appeal with the LA County Flood Control District on the following grounds:

  • Mathematical error in the calculation of the tax.
  • Significant discrepancy between the assessed and the actual impermeable area.

The appeals process and instructions are expected to be available in mid-September 2019.