We get more questions lately from people wanting a green or low energy septic system. One green concept is using the water from the septic system for irrigating plants or flushing toilets. This practice is known as reuse. “Grey water” is water drained from bathtubs and sinks. “Black water” is from the toilet.  Very strict state laws govern the disposal and reuse of sewage and water from septic systems. Many states consider all water grey or black to be hazardous based on the fact the the same bacteria are present in both although at different concentrations.

Final “disinfection” is usually required for reuse with a commercial ultraviolet unit. These types of units have been used for years in municipal treatment plants, but are relatively rare in home systems so far. UV systems require monitoring to be effective.

With the increasing value of water, reuse will become more popular in the future. For now, reuse is only available where the laws allow it. Of great importance to sewage regulation is the prevention of cross connections. This is where wastewater or irrigation water gets into the drinking or potable water system. Reuse requires modification of plumbing and septic codes. An example is inside the toilet where sewage and fresh water combine to flush the toilet. The design of toilets is highly regulated to prevent cross connections. Introducing waste water to flush the toilet can be highly risky.

Public health is dedicated to reducing the risks of microbes in sewage and in the environment from finding their way into our drinking water.reuse a

Drainage:
We can set up drainage systems for wet lots, wet basements, and general water problems.

Trenching:
With our excavation expertise, we can dig any trench you need for installation of utilities.

Sewer Hookup:
In addition to our large-scale septic installations, we also work within the city, hooking up your home or business to existing sewer infrastructure.

Demolition:
We demolish existing structures, including home, office, and commercial buildings. Typically, we haul 80% of all demolished materials off-site for recycling.

Driveways:
We build driveways to your new or existing home.


The septic tank is a watertight concrete box about 9 feet long and 5 feet tall. It is buried in the ground just outside the home. The tank is usually precast from reinforced concrete and can be purchased from concrete manufacturers. While typically designed with a 1,000-gallon liquid capacity, the size of the tank is legally determined by the number of bedrooms in the home. The tank temporarily holds household wastes and allows a small amount of pretreatment to take place.

The tank is connected to the drainfield by a buried pipe. A typical drainfield consists of two to five trenches excavated into the subsoil. In many systems, a distribution box or a flow divider helps move wastewater to each trench. In most conventional septic systems, the trenches are 3 feet wide, 2 to 3 feet deep, and 9 feet apart. In each trench, a 1-foot thick layer of washed gravel or stone is placed around a 4-inch-diameter perforated distribution pipe. After the trenches are covered with soil, the area must be landscaped to keep surface waters from ponding over the drainfield.

The drainfield has also been called the nitrification field or the soil absorption field. The sole purpose of the drainfield is to deliver wastewater to the soil. The soil purifies the wastewater by removing the germs and chemicals before they reach the groundwater or any adjacent surface waters such as rivers, lakes, and estuaries.

 McFarlane Construction, Bellingham Wa. Septic Design and Installation Whatcom County