Tightlines and Steep Slope Drainage

We Manage Drainage on Steep Slopes

Our team installs tightlines, curtain drains, channel drains, and other stormwater applications across the Olympic Peninsula. We specifically focus our stormwater and drainage applications on and near steep slopes - from the curtain drain around your house, to the tightline that conveys that water downhill.

We are the only contractor on the Olympic Peninsula who installs custom designed, built, and welded-in-place HDPE piping for tightlines. This is the standard in most new construction but is lacking in many homes built before the 2000’s. We create drainage solutions for single family, multi family, and commercial development.

Generally, our installers visit a site to perform initial stormwater mapping where all existing stormwater drainage, and recommended new drainage solutions are located and drawn out. From there, we can identify costs associated with installing the upgraded system.

Call us for stormwater mapping and drainage projects.

Tightlines (Steep slope drains) are simply drain pipes on a grade. So whenever we are moving water from one height to another height in a sloped pipe, we can call that a tightline. These pipes can be made of any material, and commonly are incorrectly installed using black-corrugated polyethylene pipe (CPEP). In our region, steep slopes tightlines should be made of solid wall polyethylene (SWPE) or high-density polyethylene (HDPE) in order to withstand the pressure of tremendous amounts of rain flowing downhill.


Developed steep slopes require a strong stormwater solution to reduce risk of erosion and landslides. Mismanaged stormwater above a steep slope is the most common cause for landslides in our region. Protect your home from landslides and excessive erosion by correctly managing your drainage. Generally, this drainage must be collected from any impervious surface, including your house, garage and asphalt.


Subsurface water can be collected and conveyed into the tightline in a number of ways. This is most commonly performed through a intercept drain (of French or curtain drain). Intercept drains can be installed in most areas to collect subsurface waterflow. We design our intercept drains differently than they would be around your home, as we are trying to collect water on a grade rather than a flat trench.

Do you have questions about your bluff?

We provide steep slope inspection services to homeowners and non-profits throughout the Puget Sound and Strait of Juan de Fuca, and we provide hydroseeding services specifically for erosion control.

hydroseed erosion control


Stormwater is rain and snow melt that runs off rooftops, asphalt driveways, paved streets, parking lots and in some situations, gravel paths and grass lawns. Stormwater in cities is a concern because of the pollutants it collects as it runs off, pollutants like oil, fertilizers, pesticides, soil, trash, and animal manure. On steep slopes, the primary concern is controlling the speed and route of the water as it flows downhill. Without this control, stormwater causes channel erosion and destabilizes slopes.


A tightline is a pipe used to convey water downhill, in order to reduce channel erosion, gullies and saturation of slide prone soils. We install tightlines using welded-in-place HDPE pipe that is secured to your slope through different anchoring techniques. This tightline moves water collected from uphill gutters, catch basins, intercept drains, curtain drains and other areas where water congregates. The bottom of the tightline is installed with a dissipater to reduce velocity before hitting the beach.

Interceptor Drains

Interceptor drains, or French or curtain drains, are subsurface drains intended to intercept, collect, and convey ground water to a proper outlet. The perforated pipes used in this application provide a dewatering mechanism to drain excessively wet soils,  improve stability of structures with shallow foundations, or to reduce hydrostatic pressure to improve slope stability.

Channel Drain

Channel drains, also called trench drains, are long, narrow surface drains that collect and convey surface water to drain pipes and catch basins. Channel drains are commonly installed in areas where stormwater runoff creates sheet flow which travels at high velocity, causing erosion. A channel drain will not collect subsurface or ground water, only water on the surface of the landscape.