How to Disconnect Your Downspout

FREE How-To Video
The City of Bremerton has created a video that shows how to separate a downspout and safely plug the stormwater connection to the sanitary sewer service. For a copy of this free video call 360-473-5929. The City will send the video via USPS mail to the address specified.

Special Case Analysis
Many properties in Bremerton have complex storm drainage needs because they are on steep hills or have other concerns. These sites will require an in depth analysis to allow the safe disconnection of downspouts and prevent potential property damage from uncontrolled stormwater runoff which is beyond the scope of the video or brochures.

Assessing Your Downspouts
Before beginning the separation project and even before buying parts, it's helpful to look at the downspout to figure out how they can be safely disconnected and divert the water away from sensitive areas of the building. Then determine what supplies will be needed to make a complete separation. The shopping list at the end of this page can be used to keep track of necessary hardware and correct measurements for the separation.

#1: Decide Where the Water Will Go

There are usually a couple of options in all separation projects. Consider these safety requirements in making a decision on how to best protect property from uncontrolled stormwater runoff after the separation is completed:

Downspout pipe is generally sold in 10-foot lengths. An extension can be cut to the desired length with a hacksaw. Also, consider the options for putting elbows and extensions together to get the water where it needs to go. For instance, you can combine elbows and extensions to send water to the side, or front, or to get around obstacles and slope problems.

Do not disconnect a downspout if it cannot meet the above safety requirements or if there are other concerns! Get help or advice from qualified people to protect property and area.

#2: Determine What Materials You Will Need

Downspout elbows and extensions come in a few standards shapes, sizes and materials. Are they round? Rectangular? Aluminum?


    1. Brackets to secure a downspout to the building (optional)
    2. Bag of quick drying concrete
    3. Cap or Plugs
      • Outside standpipe diameter
      • Inside standpipe diameter
    4. Downspout pipe extension
      • Corrugated aluminum
        • Rectangular
        • Square
      • Galvanized steel
        • Rectangular
        • Round
      • Plastic
        • Rectangular
        • Round
    5. Elbows
      • Angled to side
      • Angled to front
    6. Sheet Metal Screws
      • 2 per joint (stainless steel preferred)
    7. Splash blocks
    8. Flex-A-Spout (optional)
    9. Dripper Flipper (optional)
      • Angled to side
      • Angled to front

#3: Cut the Downspout

Reduce CSOs!

Cut the existing downspout about 9 inches above the sewer standpipe. A hacksaw should do the job. CAUTION: Aluminum gutters can be extremely sharp after cutting. Protect your hands with work gloves.

#4: Seal the Sewer Standpipe

Reduce CSOs!

Next, seal the sewer standpipe. This prevents water getting into the system. Once the downspout has been cut off, you have 3 options for sealing the standpipe.

A: To seal with concrete, get your copy of the free video to see how to use concrete to plug the standpipe for your stormwater connection to the sanitary sewer.

B: To seal with a wing nut expansion plug, make sure you have a clean mounting surface and insert the plug. Make sure the plug will seat properly and tighten the wing-nut.

C: To seal using a test cap, cut the pipe as needed. Make sure you have a clean mounting surface and slip test cap over the pipe and tighten the clamp.

Once you have sealed the standpipe have your work checked by City staff before you backfill the hole so that you can be credited for the work.

#5: Attach an Elbow

Reduce CSOs!

Insert the downspout INTO the elbow, if you put the elbow into the downspout, it will leak. Use the screws to secure it in place. You may need to crimp the end of the downspout with a pair of pliers to get a good fit.

#6: Attach a Downspout Pipe Extension

Reduce CSOs!

Use a hacksaw to cut the extension to the desired length. Attach the extension to the end of the elbow, making sure the elbow fits inside it. The required length of the extension will depend on individual situations..

If the house has a basement the downspouts must drain at least six feet from the basement wall.

If the house has no basement downspouts must drain the water two feet from the foundation (at least six feet from a nearby basement).

Using a splash block, as in step 7, the extension can be shorter, but the extension plus the length of the block must be at least equal to the minimum required lengths (six feet from a basement, two feet from the foundation if no basement).

The end of the downspout pipe extension needs to be at least five feet from your property line. More room may be needed if your yard slopes toward your neighbor's house.

#7 & #8: Secure Pieces & Splash Blocks

Reduce CSOs!

Secure the elbow and the extension with sheet metal screws. It may be helpful to pre-drill holes for the screws. Place a splash block at the end of the downspout to prevent erosion where the roof water drains.

Will the existing downspout need to be secured? Some downspouts are not attached to anything but the gutter and the sewer standpipe so it may need to be secured to the house with a bracket to keep it in place after it is disconnected.

For areas in the yard where an extension would be inconvenient or unattractive, other options exist. A device called a “dripper flipper,” a hinged downspout elbow and extension which can be flipped up against the house during dry weather or to mow the lawn, can be installed.