Green Infrastructure Maintenance

What to Do, What to Avoid

By maintaining your green infrastructure, you are doing your part to help protect the environment, local streams and watershed. There is a lot you can do to help maintain your green infrastructure feature without having to hire a contractor or landscaper. Click through the practices below to learn about routine actions that should be taken to properly maintain your features. 

If you have questions about a specific project, please reach out to our Stormwater Specialist:

Kory Kreiseder
[email protected]
609-737-3735 ext. 15

Maintaining Various Types of Green Infrastructure


Rain Gardens

To properly maintain rain gardens and bioswales:

AlwaysWhen NeededAvoid
- Inspect for signs of erosion, or obstructions

- Remove weeds and invasive plants

- Remove trash

- Make sure it does not hold water for longer than 72 hours after a rainstorm
- Cut back dead stems in March and remove from the facility

- Water plants during establishment

- Make sure there is a 3” layer of compost

- Blow out leaves in the fall
- Applying excess salt and sand around the property in the winter

- Storing snow and leaves on top of the facility

- Using fertilizer or pesticide

- Blowing grass clippings into it

Unmaintained rain gardens and bioswales may: 

  1. Stop filtering rainwater and allow trash and pollutants to enter our local streams
  2. Be difficult or expensive to restore 
  3. Allow water to pool on the surface long enough to allow insects to breed (longer than 3 days)

Green Roof

To properly maintain green roofs:

SeasonallyAnnuallyAs Needed
- Remove weeds and invasives regularly

- Inspect drains, inlets and outlets, remove any blockages

- Check the entire roof to ensure it is functioning properly and water is not ponding anywhere

- Inspect the irrigation system if applicable

- Observe health of vegetation to determine if replacement is required, coverage should be 80% or greater

- Send a soil sample out for testing
- Water the green roof for the first 18 months and during periods of drought

- ONLY if needed, apply fertilizer during the first 18 months.

Note: it is important not to have excess nutrients leaving the roof

Who is responsible for maintenance?

As the property owner, you are responsible for maintenance.

We recommend that a qualified contractor perform regular inspections.

Can I remove the green roof?

No. Green roofs are permitted structures and, in New Jersey, their proper functioning must be certified annually.

Grassy Swale

To properly maintain grass drainage swales:

AlwaysWhen NeededAvoid
- Inspect your swale after storms to make sure that rainwater has drained and there is no erosion

- Remove sediment and debris from in and around the swale
- Mow fescues and bluegrass no shorter than 2 ½ to 3 inches. Remove or compost tall grass clippings

- Manually remove any weeds or invasive plants

- Remove or compost leaves in autumn. Leaves may smother the grass and block the flow of water

- Adjust the mower height to avoid scalping the edges of the side slopes

- Reseed any bare areas and water during the initial establishment period
- Using fertilizer or pesticides in your swale

- Over-mowing or mowing shorter than 2 ½ to 3 inches

- Mowing immediately after a rain event

Unmaintained grass drainage swales may: 

  1. Cause rainwater to pool on the surface and become a breeding place for insects
  2. Stop filtering the rainwater and allow the pollutants to enter our local streams
  3. Block the flow of water and cause local flooding

Vegetated Filter Strips

To properly maintain your vegetated filter:

When NeededAvoid
- After every major storm event, every 3 months for the first 2 years, and twice a year annually after the first 2 years, inspect for vegetation density, damage by foot or vehicular traffic, channelization, accumulation of debris, trash and sediment, and structural damage to pretreatment and level spreader devices

- Regular watering may be required during the first two years while vegetation is becoming established

- Mow grass to maintain height between 50 and 150 mm

- Remove trash and debris from level spreaders, pretreatment devices and the filter strip surface

- Remove accumulated sediment

- Replace mulch

- Trim trees and shrubs

- Replace dead vegetation and remove invasive growth

- Repair eroded or sparsely vegetated areas

- If pools of standing water are observed along the slope, regrading and revegetating may be required
- Over-mowing or clipping too close to your vegetated strip. Doing so can expose bare soil and lead to dirt and sediment entering the vegetated strip

- Applying salt or sand close to your vegetated strip in the winter. Take note of whether your driveway or sidewalk drains into the vegetated strip, as salt or sand from these surfaces may be washing into them

- Ignoring your vegetated strip, do not neglect any necessary maintenance actions

Regular and effective maintenance is crucial to ensure effective vegetative filter performance.

Cisterns & Rain Barrels

To properly maintain your cisterns and/or rain barrels:

When NeededSeasonallyAvoid
- Check the entire system (e.g., gutters, debris filter, overflow pipe, fittings, spigot, etc.) to ensure the barrel is functioning properly

- Place gutter guards and/or screens on top of roof downspouts and on top of the barrel to prevent leaves and sediment from entering the rain barrel

- Remove leaves and other debris from the screen at the top of the barrel, the overflow pipe, and the roof gutters

- Regularly use water collected in your rain barrel between rain events to make sure there is room to collect rainwater during the next storm

- Drain your rain barrel before the winter season

- If your barrel has a filter screen, make sure it is intact without holes and securely fastened to keep out mosquitoes
- Unless the rain barrel is made of a material specifically designed for freezing temperatures, disconnect it during the winter to avoid damage. Around Thanksgiving, disconnect the rain barrel, and store it upside down in a protected location. Connect the barrel to your downspout around April Fool’s Day

- Open the rain barrel spigot if you expect to be away from your home for an extended period; make sure it will drain away from your foundation

- Clean the barrel using a non-toxic substance such as vinegar to remove residue or algae

- Clean out downspouts and roof gutters for the most effective mosquito control. However, if you find mosquitoes in your rain barrel, you may use dunks. A quarter dunk added monthly may be adequate for a 55-gallon rain barrel
- Leaving water in your rain barrel for long periods of time

- Drinking the water in your rain barrel or use the water inside your home or for your pets. This water should only be used as non-potable water

- Letting kids play in or around rain barrels

- Forgetting to reconnect your rain barrel every year after the winter frost season

- Spraying the water directly on vegetables or leaves, as it may contain bacteria from the roof

- Letting the barrel foundation become unlevel or unstable. A full 55-gallon barrel weighs 450 pounds and can tip over on an unstable surface.

Unmaintained cisterns and/or rain barrels may:

  1. Overflow and cause erosion near the foundation
  2. Become clogged and not allow rainwater to pass into or out of the rain barrel
  3. Become a breeding place for insects or tip over
  4. Cause ice dams in the winter if not disconnected

Dry Well

To properly maintain buried dry wells:

AlwaysWhen NeededAvoid
- Inspect your gutters and pretreatment devices after storms to make sure that rainwater properly drains to the dry well

- Ensure caps on observation wells are fastened
- Remove leaves and tree debris from roof gutters and pretreatment devices from April through November

- To prevent damage to your mower or to the observation well cap, do not mow over the caps

- Repair any damage to gutters/downspouts from winter snow or ice
- Removing a dry well or reconfiguring your downspouts to direct water somewhere else

- Placing decks, sheds, or other structures on top of a dry well

- Letting children remove the observation well caps

Unmaintained buried dry wells may: 

  1. Cause flooding on other areas of your property if the stormwater is not able to flow into the dry well
  2. Cause rainwater to pool on the surface and become a breeding place for insects
  3. Require a complete replacement of the facility which can be very expensive

Porous Pavement

To properly maintain porous pavement:

When NeededAvoid
- Inspect your porous pavement after storms to be sure water is draining through it

- Pressure wash as needed to remove sediment and prevent clogging

- Inform contractors visiting your property of the location of pervious pavement to prevent damage. Consider installing a sign identifying the material as porous pavement

- For permeable interlocking pavers, replace/replenish the top layer of stone between joints with new clean stone after sweeping, vacuuming or power washing

- Stabilize any adjacent soil areas to prevent sediment from draining onto porous pavement

- Remove leaves and debris from surfaces

- Remove snow with a rubber tipped shovel/plow or keep plow tip 1 inch above the surface. The remaining snow will melt and drain through the surface

- For commercial parking lots, use a vacuum sweeper at least twice per year to remove sediment and debris

- Stockpiling mulch, sand, salt, soil, or yard waste on porous pavement

- Piling snow that contains sand or salt on your porous pavement

- Replacing vehicle fluids or washing your car over porous pavement

- Applying sealants over porous pavement or repaving the area with materials that do not let water pass through.

- Letting large vehicles regularly drive on or turnaround on porous surfaces

- Applying sand for winter snow removal on porous pavement or on adjacent areas, such as sidewalks, that may drain onto the porous pavement.

Who is responsible for maintenance?

As the property owner, you are responsible for maintenance.

Keep in Mind:

Porous pavement needs regular maintenance to continue to filter rainwater. This includes:

  • Removing Leaves and Tree Debris
  • Sweeping

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