What is a Septic System?
Individual septic systems or Onsite Wastewater Disposal Systems are required for residential, commercial and industrial buildings that are not connected to municipal or public waste water systems/treatment plants. The Onsite systems function to receive and treat waste water (from toilets, showers, sinks, dishwashers, washing machines etc.) and return the treated effluent into the groundwater system. Designed and installed correctly, an Onsite Waste Disposal System will treat the waste stream to a very high degree, and return effectively clean water back to the ground.
An Onsite Wastewater Disposal System is composed of two parts:
- Tanks and Drain field (or septic field, leach bed, etc) the tanks serve to treat the sewage to a greater or lesser degree, and can be thought of as the Treatment System.
- The area of ground where the effluent (treated sewage) is drained into the soil is the Disposal System.
A good septic system design will consider each part of the system with equal care. A poor or unscrupulous design will address the disposal component, and gloss over or ignore the treatment component. Everyone wants the effluent to go away and never be seen again, and even a poor design will often do that well. An ethical designer will however consider the implications of disposing untreated effluent into the ground water, and ensure that the treatment system is well thought out and appropriate for the site.
Why do I need a pump? My dad never had a pump.
In the past, septic systems were usually gravity fed. If the house plumbing was deep, the septic tank and field were accordingly deeper, to allow slope from the house. This resulted in some systems that were extremely deep. It is not unusual for us to find older systems where the septic tank lid is over 4 feet down.
The problem with this is that septic systems need to be shallow in order take advantage of the aerobic soil layers near the surface. Also to keep a healthy depth of free draining soil between the infiltration surface, or the bottom of the drain field trench, and any seasonal ground water. In addition, any disposal system requiring an imported sand layer must use a pressurized distribution system (i.e. a pump).
Why do I need a Sand Mound?
On some lots, our site inspection finds that high seasonal ground water is an issue. This can be actual standing water just a few feet or even inches below the surface, or signs that the water table has been close to the surface at some point during the year. These signs usually show up as mottling in the soil, from the iron deposits being soaked and literally rusting like an old car. Other indicators are found in the soil color, and lack or presence of root growth.
In order for effluent to be completely treated it must pass slowly through 3 feet of dry soil. If you have a high water table, let’s say at 1 foot below the surface, you need to bring in 2 feet of soil (sand) to get that 3 feet of separation. Then you build the drain field on top of that….thus a mound system.
The reason this is so important is that if untreated or poorly treated effluent enters the ground water, it can migrate to a well or other drinking water source where the pathogens can cause serious illness.
Can I bury the sand mound?
We often find that in the case of new construction a sand mound can be made to disappear into the backfill. If there are high ground water issues, there is often a corresponding requirement to have a home’s living space at a predetermined geodetic height. This means usually a tall concrete foundation is constructed. When backfilling the foundation the sand mound can usually be blended in.
In cases where this is not possible, a sand mound can be made less obvious by adding free draining soil to the surrounding area.
Is there an alternative to a sand mound?
We can sometimes reduce the size and height by adding secondary treatment. When sewage is pre-treated, the resulting cleaner effluent can be introduced closer to the seasonal water table. In some cases a secondary treatment system can result in the elimination of the mound altogether.
Why does my neighbors’ new system have green lids now visible in his lawn?
Most tank lids were buried up until a few years ago. Unfortunately, out of sight is often out of mind, and regular maintenance can be neglected if septic system components are buried.
Instead, Septic Expert will add an access riser to each tank opening, with the lid installed flush with the ground surface. This ensures that baffles, filters and pumps can be quickly and easily accessed for regular maintenance. In addition, we no longer bury the entire septic field, but instead we attach a port to the distribution pipes which are left at or above grade to ensure the customer will always know where the septic field is, as well as providing a means of flushing or inspecting the distribution system.
What kind of site constraints can be overcome with a secondary treatment unit?
Sloping sites, high groundwater, fast or slow percolating soils, proximity to wetland or other delicate environments.
Why do septic systems fail?
Most early septic system failures are related to inappropriate design and poor maintenance. Some soil-based systems (with a leach or drain field) have been installed at sites with inadequate or inappropriate soils, excessive slopes or high ground water tables. These conditions can cause hydraulic failures and water resource contamination. Failure to perform routine maintenance, such as pumping the septic tank at least every 3 to 5 years, can cause solids in the tank to migrate into the drain field and clog the system.
How long will my new septic system last?
With proper maintenance, an Onsite Wastewater Disposal System designed and installed by Septic Expert will last the life of the home.
I have a slope to my property, why do I need a pump system?
Many designs involving secondary treatment, or raised systems such as sand mounds specify a pump. This is for what is known as pressure distribution. It is often a shock to homeowners because the design requires a control panel with a timer, two or more electrical circuits, and an additional tank for the pump.
This type of distribution, as opposed to a large diameter gravity pipe network, uses smaller (typically 1 or 1.5 inch) pipe to distribute effluent. This is a hugely superior method, as it allows effluent to be stored in the pump chamber and pumped to the entire disposal field at once, at preset intervals. The result is that no part of the disposal field is ever saturated, and is allowed to drain thoroughly and dry out between doses.
Why are septic systems so expensive?
As one might expect, we get this one a lot. We strive to be competitive, and ask that you compare apples to apples when obtaining quotes. Our prices are inclusive of all facets of the project.
Please ensure that competing quotes specify similar treatment levels, drain field sizes, electrical components and subcontractors. Also make sure it includes excavator charges for installation and preliminary site work.
As a rule, the cost of a new Onsite Waste Disposal System is proportional to the size of the home, and also proportional to the size and quality of the available area. So a large house on a small difficult lot can be priced much higher, whereas a modular home on and acreage might be much lower.
We suggest you consider your new Septic System as one of the many components of your home; it is likely that the price will fall in line with everything else. Septic systems are not as glamorous as a new kitchen, but it is not an area to cut corners or look for economies. Of all the systems in your home, the septic system is the one you want to continue to work properly.