Identifying a Problem

Drainage problems can cause significant damage to your home, property, and the City of Kirkland storm drain system. It is important to identify and correct drainage problems when they occur. Before starting any drainage improvements, fully identify all parts of your current drainage system. Create a detailed map of your property, showing all impervious surfaces and drainage features. Kirkland’s Public Works Department can provide plans of the City’s storm drainage system in your area, which you could use to determine how your current system is connected to the City’s system and for the installation of additional components.

Tips to Prevent Drainage Problems

To lessen the amount of impervious surface area on your property (and lessen the amount of stormwater runoff), consider concrete alternatives when planning new patios, paths, or driveways. Use gravel, paving blocks, porous asphalt, or other permeable materials.

Below are additional tips to avoid future drainage problems:

	Sweep your driveway instead of using a hose. This saves water and keeps dirt out of your drainage system.
	Avoid the use of wood chip mulch around yard inlets or swales. The wood chips float and can be easily moved by runoff water.
	Use caution when placing trees or shrubs. The roots may grow into underground drainage pipes disrupting your drainage system.
	Add screens on gutters to help keep debris out of your drainage system.
	Install a removable connection between your downspouts and roof drains. Disconnecting downspouts during cleaning will help keep debris out of your drainage system.

Installing Solutions

You as a property owner are responsible for the installation and maintenance of necessary drainage structures on your property. If your drainage problems seem too big for you to correct, there is professional help available.

	The City of Kirkland’s Surface Water Utility Engineer (425) 587-3800 is available for assistance with drainage concerns.
	There are many contractors and engineering firms that specialize in drainage problems. They can be found in the yellow pages under Drainage Contractors, and Engineers – Drainage.

The City of Kirkland requires homeowners to obtain building or grading permits before certain drainage projects are begun. To find out more information about permit requirements, contact the City of Kirkland’s Building Division Staff at (425) 587-3600.

Drainage Solutions

There are many ways to reduce drainage problems on your property. A drainage system can be installed to divert the surface water flows. You won’t need all of the items below, but installing one or several of them can make a big difference. A drainage system can be installed to divert the stormwater flows around and away from your home. Below are several possible drainage structures that can be installed.

1. Foundation drains divert stormwater away from your building’s foundation. Foundation drainpipes are perforated and usually surrounded by gravel. The pipes disperse the water (instead of discharging in a concentrated area) and the gravel contributes to infiltration of the water. The gravel can be wrapped with a layer of filter fabric to prevent the drain from clogging with sediment.  
   
   
2. Roof drainpipes are not perforated, and are not connected to the foundation drain system. They should be connected to convey water to the City’s storm drain system, to a drywell, or directly to a waterbody.  
   
   
3. Gutters collect runoff from a building’s roof. This runoff is conveyed through downspouts to the roof drain system. Gutters should be kept clear of leaves and other debris so clogging does not occur in the roof drain system. 
   
   
4. Storm drainpipes convey rainwater to the City’s stormwater system. Storm drainpipes can be made from many different materials such as concrete, aluminum, and polyvinyl chloride (PVC).  
   
   
5. Catch basins are connected to storm drainpipes. They are concrete structures (either round or rectangular) with metal grates on top. Catch basins capture debris that could clog the pipes in a storm drain system. You can prevent the system from clogging by checking the catch basins in your neighborhood during and after a heavy storm. Use a broom or rake to remove any leaves or debris that have blocked the catch basin’s grate.
   
   
6. Yard inlets are similar to catch basins but are much smaller. Metal and plastic yard inlets can be purchased at a local hardware store.
   
   
7. Trench drains are used to capture stormwater flowing over a larger area like a driveway. Trench drains convey rainwater to the City’s storm drain system.
   
   
8. French drains can be installed anywhere on your property that collects water. French drains are constructed with a perforated pipe. Gravel and filter fabric surrounds the pipe, similar to foundation drain systems.
   
   
9. Drywells can be installed in areas that cannot be connected to a stormwater drainage system. Drywells are filled with gravel and surrounded by filter fabric. Water flows into the wells and infiltrates into the ground through the gravel.
   
   
10. Cleanouts are designed as easy access points for maintenance of the stormwater drainage system. They are usually located in a bend where debris can clog the system.
    
    
11. Sump pumps (not shown in this diagram) are intended to be used as a backup system, and need electricity to function. When the sump fills with water, the pump turns on.