Planning A Home Addition In Chevy Chase

by Kevin Gilday & Tom Gilday

home-addition-under- construction A family room addition in progress on Hesketh Street Chevy Chase

Home Addition Plans: What To Do With All That Water

If you live in Chevy Chase and you are planning a home addition, you will also have to plan a "home" for all the rainwater that addition is going to displace. Montgomery County has issued rules about rain water management as relates to residential remodeling--especially for projects involving a home addition.  If the design plan shows an addition exceeds 400 square feet, the architect has to produce a rain water management plan for the property.  Chevy Chase Village takes a very strict approach by eliminating the size allowance. The problem is that buildings take away permeable surface area on your property where water would naturally percolate down through the soil and be slowly released into the ground water system. When rain falls on your roof, water is directed via downspouts and pipes into storm sewers.  That results in high velocity volumes of water barreling through the system.  That's not good.  Over many years, all that fast moving water has unmercifully gutted and eroded our beautiful stream valleys (Rock Creek, Sligo).  Further down stream the problem gets worse.   All that soil erosion contributes to dead zones (oxygen depleted areas) in the Chesapeake Bay. So... rain water from my roof top is suffocating oyster beds?  Well, of course there are other culprits (roads, sidewalks, parking lots, etc etc) but, yes, buildings and homes are a contributing factor.  It's a big problem--especially since the infrastructure is all set up to move water as rapidly as possible to ..... someplace else.

Someplace Else Is Here

In the Village of Chevy Chase, someplace else is now designated as your yard.  So, as we planned a modest home addition for a new kitchen and family room on Hesketh Street, we were obliged to comply with Village rules about water management.  Our client had two choices:

  • collect the water in rain barrels (which can be used for garden watering), or
  • dig a rain garden and pipe water from the downspouts to that location in the yard.

backyard-rain-garden-in-progress This rain garden doesn't look like much now, but in time it will fill in and blend with the greenery in the yard.

They chose rain garden.  A rain garden is a landscaping solution for controlling water on a residential lot.  An area is excavated about two feet deep and filled half way with gravel and then soil and plants that can thrive in a damp environment.  The rain garden solves the problem by providing a place for water to naturally collect and slowly be absorbed into the ground. As it turns out, our clients have always had a low, wet area toward the back of their lot that they avoided.  So, it was a perfect match.  In this case it will provide the homeowners an opportunity to do something nice (and useful) with a hereto unattractive part of their back yard. We've heard some griping about the added cost of compliance with water management rules. But so far, it hasn't caused anyone to change their mind about building an addition to their home.