Sizing your Septic Systems & Disposal Fields
The work of a septic tank is to retain and partially treat domestic water. Waste matter is discharged from the tank to land via perforated pipes installed underground. Septic tanks are best installed where soil properties are good and where the depth of soil above the ground water table is sufficient. Septic tanks serve well where populations are sparse. Disposal field considerations do not allow more than 150 people to use one septic tank.
On its own, a septic tank cannot treat water adequately. Its main role is to make sewage waste cause less clogging in the disposal fields. It works in such a way that it settles or floats solids until they accumulate. The remaining liquid flows out via an outlet just beneath the floating materials.
A septic tank with one compartment provides minimum treatment to a household’s wastewater. On the other hand, a septic tank with multiple compartments will give better results. Such a septic tank will totally suspend solids while settling the heavier materials at the bottom. Having multiple compartments helps to prevent solids carry-over into the outlet pipes.
A septic tank is sized based on the anticipated flow from a household with a retention time of 24-48 hours. The bigger the tank, the longer it can retain, and the better it will be for the property owners. The recommended capacities for septic tanks are:
- 1-2 bedrooms — 3.6 m3 (800 gallons)
- 3 bedrooms — 4.6 m3 (1,000 gallons )
- 4 bedrooms — 5.5 m3 (1,200 gallons)
- 5 bedrooms — 6.4 m3 (1,400 gallons)
- 6 bedrooms — 7.3 m3 (1,600 gallons)
When there is a lot of sludge at the bottom of the tank, the capacity of the tank and its detention time will go down. This in turn makes the treatment less effective. To prevent this, you will need to pump out the tank every 3-5 years. However, if you hire inspectors in between, they will know how much scum and sludge has accumulated and the right action to take. When disposing the sludge, a licensed hazardous waste company, like McRae’s Septic, will take care of it in an environmentally-friendly way.
Before you install, repair or upgrade the septic system, ensure that it meets all the legal requirements. For more information on this, contact your the local public health offices near you. Make sure to ask them all the questions you may have concerning septic tanks to avoid breaking the law and have them installed in the right way.
At McRae’s Septic Tank, our company has the equipment, trucks and expertise for your next septic inspection or pump out. Give us a call for your free quote in Langley, Surrey, Delta, Abbotsford, Coquitlam, Port Coquitlam, Maple Ridge, Chilliwack, Fraser Valley and Metro Vancouver!