Rainwise Rain Garden Checklist

Step 1: Verify RainWise rebate eligibility

Step 2: Verify at least 400 square feet of roof run-off will be captured

  • This is minimum RainWise rain fall catchment area required by the Rainwise program.
  • Gutters and downspouts may need to  be rerouted or configured to maximize water capture – the Rainwise rebate covers this element of the installation but substantial gutter work may decrease your cost/rebate ratio.

Step 3: Verify an appropriate location for a rain garden exists on your property

  • The required set-back from a house with a basement is 10’
  • The required setback from a house with no basement is 5’
  • Your rain garden must be 2H away from any retaining walls (i.e. rain garden must be 6’ away from a 3’ retaining wall). Additional considerations apply if your retaining wall is more than 4’ tall.
  • Your rain garden must be installed with an overflow outlet to accommodate very heavy storm surges. The overflow must be adjacent to a sidewalk, driveway or street or be piped back into  your functioning side sewer stand pipe.

Step 4: Measure soil drainage rate

  • The drainage rate of your soil is a key factor in determining the size of your  rain garden.  Sandy soil drains faster, clay soil drains slower.
  • This easy test requires observation of the soil drainage rate over 5-6 hours of time.  This test is not necessary for cistern-only installations.
  • This formneeds to be filled out by you in order to move forward with a rain garden design.
  • This will be homework for youunless you want to pay us to do it for you.

Step 5: Understand rebate coverage and expense obligations

  • Seattle Public Utilities pays $3.50 per square foot of  roof runoff being captured by a rain garden.
  • An average rebate from Seattle Public  Utilities is $3000-4000, which covers 50-100% of the project costs.
    • Factors impacting overall project cost include: access on your site, style, slope, topography, roof-lines, gutter work, size of garden, types of plants, etc
  • You need funding available to cover the costs of the project  
    • You will need to have the project cost (approximately $3000-$6000) available to cover costs for our time and rain garden materials upon completion but prior to receiving the rebate.
    • We require a 50% deposit and the balance upon  successful completion of the final inspection with SPU.
    • SPU will generally reimburse you within 30 days of receiving your rebate package

Step 6: Consultation and Design

  • The first 20-30 minute site visit is complimentary to check on RainWise viability (rain garden and/or cistern) and rough specifications.
  • Assuming your site is suitable for installation and you want to move forward, a detailed design is required by Seattle Public Utilities.
    • Design time is $85/hr, and usually takes an additional 3-12 hours(depending on the complexity of your site), and is provided to you for:
      • RainWise’s requirements, and
      • Your broader landscape purposes (if you’d like a design beyond Rainwise-specifics)
    • You and Contemporary Homestead will co-sign a design contract before proceeding so expectations are clear.
    • We’ll take detailed roof catchment, rain garden footprint, slope, and topography measurements.
    • We will also discuss your goals and objectives, plant preferences, etc
    • Your completion of the comprehensive questionnaire serves as a great jumping off point for design vision and goals.
  • We design various styles of rain garden and try to incorporate multi-purpose plants. Plantings typically include:
    • Sedges, Rushes, Sweet Grass, berries, and flowers.
    • No annual veggies or root crops because of heavy metals from the roof, but berries work great (elderberry, serviceberry, huckleberry,       etc.)
  • Designs include a project cost estimate, plant list, and planting plan. Additional features may result in additional design time.
  • Design time will include 2 hours specifically for SPU pre- and post-inspection meetings.

Step 7: Installation and Inspection

  • First Seattle Public Utilities (SPU) meeting
    • We meet with SPU at your house to review the design and implementation plan for your rain garden/cistern
  • Installation
    • We build your beautiful rain garden cisterns
  • Second SPU Meeting
    • Follow up meeting with SPU to review installation
  • Project Invoice
    • We send you the final invoice and several pieces of related documentation required by Rainwise for the rebate.
  • Rebate Application
    • You, the homeowner, complete a rebate application formand submit it to the city, using the instructions on the form.
    • Note that SPU requires the completion of a W9 form to obtain the rebate. You will be asked to provide your social security number and your rebate will be taxed as income via SPU.
  • Project funding
    • We invoice you for the work performed and receive payment upon completion
    • SPU sends rebate check for $3.50/ square foot of roof area redirected, generally within 30 days.

Factors in the rebate cost-benefit equation

  • The cost vs rebate depends on the square footage of roof  we can redirect to a cistern or rain garden (400 sf min).  The more roof square footage captured, the more rebate money you will receive to apply to project costs.
  • If you have the option to choose between a rain garden or a cistern, a Rain Garden gets more rebate value. When you combine a cistern and a rain garden together the larger rain garden rebate applies.  
  • Generally, the cistern rebate covers the installation and pays for itself. A larger cistern gets a larger rebate, but also costs more.
  • Our initial planning time is spent determining logistics and scenarios so you can choose the best one.  Whether you go with a rain garden, a cistern, or both, there are design + admin costs (including meeting with SPU, for example)
  • For rain garden design, we typically need at least 2-3 hours to get an accurate base plan (foot print of the house and relationships of house to other features on your property), and 3-5 hours to cover the bare minimum of our  design/planning/meeting/administration time.  We cannot afford to give this time away.

Sound good? Then please contact us! We look forward to helping you become Rainwise!