Septic system cost is critical to know before you start your building project. In fact, it is prudent to have a good idea of the costs before you even buy land.
If you want to live off the grid, every rural parcel will require a septic system that meets with county regulations. Most counties in most states will require evidence of working water supply and septic system before issuing a building permit.
Septic systems are like miniature waste treatment plants. If you have not experienced a septic system before, they are nothing to be scared of. There are regulations to be followed to ensure public health and safety is maintained when you create your delightful homestead. A licensed contractor will help you work out your septic system cost and ensure your county rules are adhered to.
If you are based in a small country town, you may be able to connect to community water and sewer system but for the most part, it is not unusual to install your own septic system as part of the build. These days, modern septic systems work very well.
It is important to have a basic understanding of what goes into septic system design and installation to make sense of the septic system cost.
It will help you better understand where to spend money and where you can cut back.
Several types of septic systems are used across the country, but the most common is the septic tank/absorption (leach) field system.
Everything that goes down every drain and toilet in your house will go into this pipe and into the septic tank.
The septic tank may be made of fibreglass, wood, concrete, plastic or polyethylene. Probably the majority in the USA are made from concrete but polyethylene tanks are becoming more popular. These do not crack or leak and they are easily moved around by two people.
They will save you money on your septic system cost as they require less heavy equipment and are easier to install in tricky locations.
Waste stays in the septic tank long enough for solids to settle out as sludge and for grease and oils to float to the surface as scum. Specially designed outlets in the tank hold back sludge and scum, while allowing the relatively clear middle layer — known as effluent — to enter the drain field.
Microbes in the soil digest or remove most contaminants from the waste-water before it reaches groundwater. Sometimes the effluent is internally piped to a second compartment of the septic tank for additional settling and then flow out to the leach field.
Some septic systems use a pump to help push the effluent through a pipe to the distribution box (D-box). This D-box evenly distributes effluent to different pipes in the leach field.
The typical leach field is a series of rock filled trenches where effluent is further treated as it slowly percolates through the soil. A leach pit is a deeper, larger hole filled with rock for disposing of wastewater in a smaller footprint.
The solids that are heavier sink to the bottom of the septic tank. Anaerobic microbes live and feed on the biological matter. They do not require oxygen to live and they reduce the amount of solids in the tank and reduce the concentration of dissolved biological matter in the liquid.
The leach field is the most important part of a properly functioning septic system.
It is also the most expensive part of the septic system cost. It is easy to damage and expensive to replace.
Before starting your project, you will need a percolation test. Factor this into your septic system cost. The size of the leach field will depend on the results of this test. The local building code will then dictate how many square feet of leach field is required based upon the speed of percolation and the composition of the soil.
A general rule-of-thumb to use when estimating is one square foot of leach field, per gallon of effluent, per day, in normal soils that percolate relatively well.
The leach field is typically a set of pipes with small holes in the bottom that lay in a trench allowing the effluent to flow into the soil after first flowing over gravel.
The pipes are covered with additional gravel and finally topsoil.
The flow of the liquid down through the gravel and into the surrounding soil pulls air down into the soil where oxygen using microbes are to further break down the dissolved biological matter.
Further down the soil depth where no oxygen is present other microbes finish the biological treatment process.
The soil itself also acts as a filter to remove many of the other chemicals and minerals in the effluent.
If the pipes in the leach field get blocked or do not disperse the fluid, the septic tank will overflow and can back up into the home.
The most common reasons for leach field failure are:
1) Only using a single compartment septic tank
2) Absence of a particulate filter
3) Leach field is too small
4) Poor ventilation in the leach field.
Even in a warm climate, septic tanks are able to maintain healthy bacteria levels and 'digest' sewage more readily when warm.
Bedding a septic tank in gravel can makes the difference between having your tank pumped every three years to maybe once every five or six years.
Conventional field lines consisting of gravel top and bottom are available. Or there are newer one requiring no gravel and less field lines. Discuss with your local contractor and see what is recommended and available in your State.
Here is a great overview to improve your understanding of how septic systems work:
Factor regular inspections into your septic system cost and pump as necessary. Make sure you seek out a licensed professional. Keep good records of repairs, inspections, pumpings, permits issued and any other septic maintenance activities.
Here are some important dos and donts when it comes to looking after your leach field:
Don’t drive over your leach field because this will compact the soil and reduce its ability to accept liquid and transfer air.
In severe cases, the weight of the vehicle could crush the pipes. Don't allow large animals over it either as they will compact the soil.
Do not dispose of household hazardous wastes, paints or cooking oils in sinks and toilets. These can kill the vital microbes in the entire septic system and in severe cases clog the leach field leading to total system failure.
Don’t put items like dental floss, flushable wipes, coffee grounds, cat litter, pesticides, cigarette butts, cotton balls or swabs, diapers, condoms, and feminine hygiene products into your septic system.
Never use bleach, drain cleaner, or harsh soaps with a septic system. Bleach and detergents kill the helpful bacteria that thrives in a healthy septic tank to optimally process toilet waste. Lack of proper septic tank bacteria will cause your leach field to fail from excessive bio-mat accumulation.
Do check the vent pipes now and them and ensure they are clear. Sometimes they can get blocked by debris or small animals which clog it and prevent free flow of air.
Use septic-system friendly toilet paper, laundry detergent and bathroom cleaners. Try baking soda and vinegar!
You want to encourage helpful good bacteria (digesting anaerobic cultures) to grow in your septic tank and organically treat the waste, not kill helpful bacteria with detergent laden graywater.
Don't place anything on top of the leach field because it will interfere with the proper airflow into the ground. This includes not planting anything other than grass over the leach field in case roots grow down and damage it.
Of course, if you notice any problems, address them right away. Ignoring them will not fix them
It is better to address any issue early and perhaps replace a small part than have the total septic system fail, back up sewage into your house and have to install a new system and replace every contaminated item in your house.
Alternatives to a leach field do exist. These include: pressurised mound systems, evapotranspiration, drip beds,cesspits and constructed water treatment wetlands.
Check with your local contractors what is permitted in your area.
You local contractor will advise you at the time of installation but plan on having your septic tank pumped every three to five years. Regular inspections and pumping as necessary to keep your septic system in good working order. Septic pumping prevents build-up of sludge and floating scum which could cause septic system failure and expensive repairs or replacement.
Septic pumping could be required less often in warmer areas or if there is lower usage.
Check both septic tank compartments yearly and pump before enough solids accumulate in first compartment to potentially to spill over into second compartment.
Sizing with greatly affect the septic system cost. This will be determined by the demands placed on the septic system such as:
How many bathrooms will feed into it?
How many other plumbing fixtures likes taps, sinks, showers, dishwashers, washing machines and bathtubs?
How many people live in your household or building?
Your contractor or the local permit office will advise you according to the local rules.
For example, depending on the State, a 3 bedroom house with 2 bathrooms and 25 plumbing fixtures may require a 1300 gallon tank.
A building with 14 occupants and 4 bathrooms may require a 2000 gallon tank.
If you are deciding between two sizes, always go for the slightly larger one. It will save septic system cost in the long run as you will need to get it pumped less often.
Plus installing a larger tank now will allow for more people to live there later or adding further bedrooms later on without having to rip out the smaller one and install a larger one later.
For most homes in most states a 1500 gallon drum with two compartments is often used. The septic tank will have access hatches for inspection and pumping.
The first step is to apply for a permit to install your septic tank and field line sewer.
The health department will guide you through the steps.
You will need a percolation test. This test will indicate the porosity of the soil and how many feet of field lines will need to be installed.
The local planning department will assess soil conditions, groundwater, or bedrock in the area where you intend to put the leach field. They will also advise on setbacks from buildings, wells, streams, and property lines.
The actual tank size required will depend on the number of bedrooms and people living at the site and the percolation test has no bearing on it. Be sure to bring in legal documents showing ownership and property dimensions.
Make sure you get an approved tank with State approved materials. As sewerage can be highly toxic (and poor sanitation is responsible for millions of deaths each year around the world- mainly in less developed nations), this is highly regulated industry to protect all citizens from shoddy workmanship and poor sanitation.
Whilst it may be possible to do a lot of the work yourself to save significant septic system cost, it is best left to a pro. It is fairly technical and a lot could go wrong. Having to start over and replace a dodgy system will cost more in the long run than getting it done properly in the first place.
The cost to build a septic tank system varies widely from as little as $1,500 to circa $5,000. Modern septic systems that are well looked after and regularly maintained, should easily last 20-40 years. Be sure when you consider the total septic system cost when you are doing your budget to buy land. This is not insignificant and must be done at the beginning.
This cost refers to a standard or conventional gravity system for a 3-bedroom home on a level site with good soil.
Always get a few quotes from qualified local contractors to determine the true cost for your project in your county.
Here is a septic system cost breakdown:
The septic tank itself may cost $600 to $1,000.
Gravel trenches are the most common type of septic soil absorption ﬁeld used in the United States. Expect to pay $12 to $30 for 1 ton of drain gravel.
Piping carries waste from your house to your septic tank and then from your tank into the drain field. Costs will vary according to the size and design of the system. For reference, 100 feet of 4-inch perforated PVC piping costs $65 to $80.
A septic tank riser allows above-ground access to your tank and can considerably reduce the cost of maintaining your system. Septic tank risers are commonly made from polyethylene, PVC or concrete. Concrete risers are the cheapest (approximately $100), but they’re heavy and can be difficult to install. A riser made from polyethylene or PVC will typically cost $200 or more, depending on size.
The building permit itself may cost a few hundred to a few thousand dollars. But it is essential.
A soil percolation test will generally cost $100 to $400.If you need help identifying skilled septic professionals in your area, you may want to contact the National Onsite Wastewater Recycling Association. Your local public health department or planning department may also be able to recommend some approved contractors.
In most areas of the country, septic system cost for a normal property will be $2K-$4K. It could be slightly more or slightly less depending on size, complexity of the system required, layout of the land and soil quality.
Naturally there is some upfront cost but overall it should be cheaper than installing a new bathroom with standard plumbing and normal plumbing fees.
If you have never installed a septic system before, do not be afraid. A good local contractor will guide you through it and ensure all the correct forms and plans are submitted and approved.
It makes sense for the counties to ensure everyone’s septic systems are fit for purpose and installed correctly to protect the health of local communities.
The other factor to consider when buying land is the size of the plot.
Due to the size required for the leach field, is why counties will not permit a house build on smaller parcels of land. For example if a leach field need to be ⅓ acre but the plot is only 1/2 acre, then there is no room for a house as well! Check this with your county planning department.
Some 1/2 acre or ⅓ acre plots will support a single family home if the dwelling is small enough.
In general, parcels over ¾ acre and 1 acre should be fine. Always double check this. If you are looking at a small plot within city limits that has access to city sewer, there is no problem with smaller plots as a leach field is not required.If you are looking for rural land, check out our current listings here.