What are BMPs

Get Small BMP Retrofit Plans approved electronically

Homeowners, contractors, and consultants can submit plans for small BMP Retrofit proposals that disturb less than 7 cubic yards and get an approval online.

*You are now allowed to pave up to 400 Square Feet with a Small BMP Retrofit Plan

Applicants should be prepared to submit 3 items through the TRPA Citizen Access Database for a quick and easy paperless process. No trips to the TRPA offices!


Required Three Items

1. Site Plan that includes:
     • Parcel Boundaries
     • Map scale (if applicable) and north arrow
     • Assessor's Parcel Number (APN) and property address
     • Location and label for all BMPs to be implemented
     • Existing coverage (building footprint, driveway, walkways) and stormwater flow lines
     • Locations of stream environment zones (SEZ), if present


2. BMP Treatments Form


3. Calculation Spreadsheet

Small BMP Retrofit Plan detailed instructions
Example 1 of a Small BMP Retrofit Plan
Example 2 of a Small BMP Retrofit Plan


Standard Conditions for applicants using the Small BMP Retrofit plan

• Approval of the type, sizing, and location of BMPs is based upon the reviewer’s assumption that the applicant has accurately and completely measured impervious areas contributing to infiltration systems.

• All areas displaying erosion or bare soil must be noted on the site plan and re-vegetated or otherwise stabilized. Vehicular access must be limited to paved areas in order for a parcel to be eligible for Certificate of Completion of BMPs. Parking barriers may be necessary in order to be compliant with this requirement.

• Small BMP Retrofit plans are not a verification of land coverage, land capability, or use, nor are they a conceptual approval of any future project. Land coverage cannot be verified, transferred or banked through a Small BMP Retrofit plans. These verifications require the submittal of a separate application to TRPA for review and approval.


If any of the following conditions apply to the proposed BMP installation then a BMP Retrofit Permit application or another TRPA application may be necessary and the project will NOT be eligible for a Small BMP Retrofit Plan approval.

• Engineered structures, such as retaining walls over 3 feet
• Extensive grade alterations
• Infiltration systems capturing runoff from areas greater than 2,500 square feet
• Excavation of over 5 feet
• Paving over 400 square feet
• Subsurface conveyance systems (piping) and drop inlets
• More than 7 cubic yards of grading