Above Ground Septic Tanks: A Review

In general, above-ground septic tanks (also called "holding tanks") are wastewater storage tanks which sit above the ground. Small, portable polyethylene tanks are made in 250 and 350 gallon sizes, and these are appropriate in some situations for temporary storage of sewage. Above-ground tanks may also be appropriate in water-front areas where below-ground storage and leaching is prohibited.

How Above-Ground Septic Tanks Work

An above-ground septic tank is a type of septic system that is installed above ground level. In most cases, wastewater flows from the home to a septic tank, then via gravity to a pumping tank which pumps it to a sand mound located above ground level, where it is evenly distributed throughout the drain field. The tank for both above-ground and traditional, below-ground septic tanks is a large container that acts as a reservoir and holds water, waste, and sewage before it is discharged onto a leach field (aka discharge area). Above-ground septic tanks work exactly like traditional, buried tanks, separating solid and liquid waste and allowing them to be taken away without harming the environment.

The primary advantage of an above-ground septic system is that it can be used when site conditions are not suitable for installing a conventional septic system due to the increased risk of the system failing. They are often used with mobile homes and RVs. However, there are several scenarios here it simply isn't practical or safe to employ this method, and an alternative solution is needed. If you need an above-ground septic tank, chances are you'll also need to hire a professional wastewater removal company to come and drain the tank and remove the sludge and scum regularly. Extra planning and permits are also necessary when installing an above-ground septic tank & system.

The Drawbacks of Sewage Holding Tanks

While holding tanks are occasionally used in seasonal cottages that don't have up-to-date plumbing options, permanent above-ground tanks are rarely used (at least in the United States). They suffer from a number of drawbacks:

• If they are not paired with a leaching field, they need to be emptied regularly: an often unpleasant (and potentially expensive) task.
• If the above-ground tank does work in conjunction with a leaching field, the sewage is typically transported into the tank via a pump (rather than gravity.) This can cause the solids in the sewage to be chopped into smaller pieces, and to escape the tank along with the effluent. As the solids settle out of the effluent, they can block the pipes that lead to the leaching fields.
• Since above-ground tanks are exposed to the elements, they have a tendency to wear out more quickly than their cousins buried under several feet of earth.

Above-Ground Septic Tank Cost

Above-ground septic tanks can vary widely in cost, depending on their size, material, and features. On average, a small, portable polyethylene tank can cost around $500-$1000, while larger above-ground tanks can cost upwards of $3000 or more. Large units designed for community systems cost $7,000 on average but prices can vary wildly depending on the project.

The installation process itself involves preparing the site for the tank by leveling the ground and ensuring that it is stable enough to support the weight of the tank. The tank is then placed on the prepared site and connected to the plumbing system of the home. A professional should be hired to install an above-ground septic tank to ensure that it is done correctly and meets all local codes and regulations.

Labor makes up 50% to 70% of your total project cost. In a typical installation, labor is more expensive than the price of the tank itself. Whereas the tank size needed for a three- to four-bedroom home may cost $1,000 to $1,500, the cost to install can range from $750 to $4,000.

Above-Ground Tank Care

Above-ground septic tanks require regular maintenance and care to function properly. Here are some steps homeowners can take to keep their above-ground tank in good working condition:

1. Pump the Septic Tank Regularly: One of the most important tasks that you will need to arrange about once every two to five years is having the septic tank pumped. The frequency of pumping depends on the size of the tank, the number of people living in the home, and the type of waste that is put into the septic system.
2. Inspect the System for Leaks: Regularly walk around the septic system and keep an eye out for any areas around the tank where the grass is significantly more lush or dense than other areas of the yard. A leaking tank provides ample nutrition for plant life and can also give off strong sewage smells.
3. Use Water Efficiently: The more water a household conserves, the less water enters the septic system. Efficient water use improves the operation of a septic system and reduces the risk of malfunctions.
4. Properly Dispose of Waste: Make sure to properly dispose of waste, such as not flushing non-degradable products down the toilet, to prevent clogs and backups.
5. Maintain Your Drainfield: Do not park or drive on your drainfield and plant trees an appropriate distance from your drainfield to keep roots from growing into your septic system.
6. Keep Accurate Maintenance Records: Keep records on work performed on your septic system, such as when it was last pumped, to help you stay on top of maintenance tasks.