Private Stormwater System Management

Private Stormwater System Management

Bainbridge Island has public and private stormwater systems working together to prevent flooding and pollution. The City is responsible for the Island’s public stormwater system and more information is available on our Public Works’ Operations and Maintenance page. Private property owners are responsible for their own private stormwater systems. If you’re not sure if you’re responsible for a private stormwater system, contact us.

Private stormwater systems provide for collection, conveyance, flow control, and sometimes water quality treatment; and they might include a combination of the following components:

  • Roof gutters and downspouts
  • Catch basins
  • Pipes (underground and/or aboveground)
  • Culverts
  • Swales
  • Ditches
  • Ponds, tanks, vaults, etc.
  • Filters
  • Permeable pavement
  • Rain Gardens
Stormwater Maintenance Tools

General Stormwater System Maintenance Requirements:

  • No pollution – “Only Rain Down the Drain” Prevent anything but rainwater from entering any stormwater drainage facility or system and immediately remove any pollution that is found in your stormwater system.
  • Safe access – the ability to safely inspect, operate and maintain
  • Functional and structural integrity – ensure the system is working as designed and constructed, and is maintained to standards (e.g. no broken parts, no cracks or holes, no erosion, etc.)
  • Reducing debris and sediment load – prevent and remove sediment and debris that may block pipes or the facility from functioning as intended
  • Vegetation management – plant, cut, remove vegetation as needed
  • Good housekeeping – use, store, and dispose of household waste, yard waste, and hazardous waste appropriately


Benefits of actively managing stormwater on your property will… 

  • Protect people and animals
  • Increase safety and decrease liability
  • Maintain your property value
  • Minimize and/or eliminate flooding
  • Prevent high-cost damage and/or repairs
  • Improve site aesthetics
  • Comply with environmental laws
  • Reduce the amount of pollution in our Island creeks and Puget Sound

Tips for Inspecting and Maintaining a Private Stormwater System

  • Be smart and be safe.
  • Annual inspections are recommended and in some cases are required. Frequency depends on need, legal requirements and/or your Operations and Maintenance Plan. To help guide your inspection, use the maintenance standards provided in the 2019 State of Washington Department of Ecology Stormwater Management Manual for Washington Western
  • Maintain your system based on your inspection. Perform maintenance as needed and in a timely fashion, don’t wait to get to done unless it makes sense to.
  • Consider hiring a professional service contractor. Contractors are available for inspection and/or maintenance that is outside of your comfort or abilities.
  • Use the buddy system. Perform inspection and maintenance with at least one other person.
  • Do not enter any underground structure unless you and your buddy have a current confined space entry certification and fall protection equipment setup. Instead, use a flashlight, a mirror, and a probe stick.
  • Make yourself visible by wearing bright or high-visibility clothing. Use signs and cones when in areas where there is vehicle traffic.
  • Consider the weather. Inspecting or conducting maintenance in heavy rain, snow, or in icy conditions is NOT recommended.

Use personal protective equipment (P.P.E.) such as:

  • A cell phone or other way to call for help in an emergency
  • Gloves
  • Work boots or sturdy shoes
  • Flashlight or headlamp

Budget for maintenance. Develop and implement a long-term maintenance plan and funding strategy to accomplish routine and non-routine maintenance.

Keep Records. Keep a log of all inspection and maintenance activities. Also keep a map or diagram of your system, all its components and where they’re located.

Keep in touch with the City NPDES Permit Coordinator. The City wants to help you to help yourself because private stormwater systems play a vital role in the health of our Island and Puget Sound.

If you want to learn more about how to inspect and maintain your private stormwater system, some technical assistance is available if you contact us.

Contact Us

  1. Water Resources