Storm Water Quality

Contain the Rain

Rain garden.

Learn about appropriate Green Stormwater Infrastructure by visiting the GSI webpage.

Click image to submit your pledge.

A downspout extention.
Downspout extensions direct water flow to the lawn and contains storm water on your property.

What does it mean to ‘Contain the Rain’?

By containing the rain on your property you are helping to reduce the amount of rain water that runs off. This in turn reduces pollution, water flow and erosion, flooding, and recharges our ground water.

What are ways to Contain the Rain?

Rain barrels, rain gardens, planter boxes and permeable pavers are all examples of green stormwater infrastructure (GSI).

For more information and guidelines on green stormwater infrastructure you can install at your home, download our manual. For tips on storm water landscaping, check out these pages from our Healthy Yard Care guidebook. For information on green stormwater infrastructure for a variety of settings check out the Green Stormwater Infrastructure webpage.

Join us at one of our upcoming Storm Water Management for Homeowners workshops

Join us for this exciting hands-on workshop featuring:

  • Assessments of property water flow
  • Selection of potential project areas
  • Ins and outs of installing downspout protection
  • Installing planter boxes
  • Installing rain gardens
  • Installing permeable hardscapes

Click here to sign up to be notified when workshops are scheduled.

Downspout Redirection

A simple way to Contain the Rain is to direct downspouts from your roof gutters towards planted or gravel covered areas. However, there are a few things to consider before doing this:

  1. Do not allow downspout discharge to flow toward the building, as this could result in damage to the building and/or its foundation. For houses with post and beam construction, uphill downspouts may be piped beneath the building for discharge on the downhill side.
  2. Flow channel should be at least 10’ away from structural items (foundations, piers, or retaining walls).
  3. Avoid directing water toward areas where ponding already occurs. This indicates poor draining soils which will need amending to improve drainage. Learn about testing drainage rates HERE
  4. Provide a splash block to prevent erosion where a downspout discharges to the ground. If the area around the splash block is steep and/or has sparse ground cover, be sure to stabilize the area with gravel, mulch, or other means to adequately prevent soil erosion.
  5. Do not direct water flows toward neighbors if less than a 15’ of channel flow or if a large quantity of water flows from the downspout.
Useful materials include splash blocks, extension tubes, stealth flows, dripper flippers, and catch basins. More information about these and how to install them can be viewed HERE.

Rain Barrels

Another way to Contain the Rain is to collect rain water from your roof with a rain barrel or other storage container. Below are a variety of resources to get you started.

Watch this Informative Video to Learn how you can Install your own Rain Barrel.

Review PowerPoint slides from our workshop presentations for a good overview of how to install a barrel using a diverter kit.

How to get container for your rain:

  • Any container can be converted, outdoor plastic trash cans are inexpensive and readily available at various retailers especially home improvement stores.
  • Hardware Hawaii in Kailua has new high grade barrels for sale.
  • Various other food grade barrels are available from food manufacturers and sometimes offered by individuals on Craigslist, OfferUp, or other want ad sources. A table of a few sources is here.

How to get your own Diverter Kit:

Note: homes need to have gutters and downspouts and a power drill is needed to install the kit components.

Diverter kits are patented and manufactured by EarthMindedTM. Additional kits or parts are available from a number of online distributors as well as at Hardware Hawaii stores.

Diverter Kit Installation Instructions: English, IlocanoTagalogVietnamese, ChineseSamoan.

Rain barrel.
Rain Barrel Diverter Kit

Other Options:

Honolulu Board of Water Supply is offering a rebate when select rain barrels are purchased, they also have more information and workshops about water conservation including rain barrels.

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