Septic Tank Installation

Septic tank installation requires a good deal of labor and specialized equipment for digging the ground and moving the tank. Traditionally, tanks were made from heavy concrete, which made them quite durable. Concrete tanks are still made today and are sometimes, but not always, furbished with risers (see our septic riser article before having a tank installed). Modern materials are lighter in weight, and include polyethylene and fiberglass, both of which can be expensive. Quality will determine the tank cost, regardless of the material.

A septic tank installation includes setting the tank in the ground and installing septic pipes which connect your home main pipe to an inlet in the tank. Waste from your home flows into the tank, allowing solids (oils and grease) and liquids to separate, and liquids to drain into the septic field. The oils and grease float to the top as scum and must be evacuated periodically by a septic tank cleaning service, who transfer it to either a recycling facility (ideal) or a landfill.

Septic tanks are robust, but occasionally wear out or are damaged. One way they can be damaged is by vehicles driving over them (be very aware of your septic tank and field when having contractors on your property). While some tank damage can be repaired, sometimes the tank will need to be replaced. If you purchase a small home and have a big family, or upgrade/enlarge an existing home (and have a big family), your existing tank may be inadequate for the usage and may also need to be upgraded.

Signs of Septic Failure

• Gurgling drains and backup in your fixtures.
• Soggy areas of abnormally green grass (if this is near your tank, you may have a leak).
• Bad odors (septic smells).
• Toilet flushing issues.
• Pooling water, either outside or in your basement.
• Slow drains.
• Water backup in your plumbing system.

Some of the above issues could simply indicate your tank needs to be pumped out, but there are numerous other reasons for failure including clogged pipes, tree root systems invading and plugging pipes, and damaged outdoor pipes or field (caused by vehicles or heavy equipment). Sogginess and unusually green grass in your tank area are the biggest indicator of actual damage to your tank, whereas, many of the above symptoms could simply be caused by an overfilled tank. If you have a tank riser on your tank (which provides easy access), the septic tank is probably the first thing to inspect before hiring a septic snaking service.

Most Common Causes of Septic Failure

• Dumping grease and solid waste in your kitchen sink.
• Garbage disposals (many plumbers suggest not using them when you have a septic system).
• Thick toilet paper.
• Flushing improper waste down toilet.
• Tree roots getting into pipes.
• Deformed/collapsed tanks (caused by ground water pressure).
• Over-taxing plumbing systems (i.e., under-sized septic pipes installed in large-family dwellings or under-sized septic tanks that overfill).
• Damaged pipes, tanks and fields caused by vehicles and heavy equipment.
• Excessive rains or snow-melt can flood septic fields and cause backup.

Septic Tank Installation Cost

Should you discover that your tank is damaged, the first step is to repair it. If it can’t be repaired, or you simply need an upgrade, you’ll have to pay for a full installation. The tank itself is only a portion of the cost. A 1000-gallon concrete tank costs between $500 and $1100. A 1000-gallon single polyethylene tank can cost $600-900. A 1500-gallon plastic tank can run as high as $1600. A small home with one or two people could get by with a 500-gallon tank, which is somewhat cheaper, but know that, the smaller the tank, the more frequently you will need to get it emptied. Read our septic tank cleaning guide for more information. Many larger homes with multiple baths and inhabitants have multiple-tank systems, making the materials portion of your installation cost more. There are also pipe, seal and fitting expenses.

The installation itself is very laborious and requires special equipment, as mentioned above. Concrete tanks may cost more because of the extra care and equipment needed to transport and install them. Ask for recommendations from your septic professional on which type of tank is best for your home. Installation can range in cost from $1500 to $5000 (or higher), depending on your tank size, configuration, and other requirements. Obviously, the complexity of your septic system and your waste removal requirements have an enormous impact on what your septic installation costs. An elaborate system in a huge home could be as much as $15000.

Installation may include removal and disposal of old tanks and pipes, and always entails land excavation, cutting and fitting of new pipes, and tank placement, and replacing of dirt. You may also want to figure in post-tank installation landscaping into your budget (the septic people will not do much in the way of landscaping).

What is the Best Type of Tank to Buy

What type of tank to buy, really depends on your needs for waste removal, your budget, and your warranty needs. Concrete tanks can last for decades, but they can also be susceptible to cracking due to driving over them or from getting overfilled. Any tank will last longer when it’s properly maintained. Plastic tanks are lighter and easier to install (and remove), but they may have shorter warranties and shorter life expectancies. There could be potential issues with deformation from groundwater with some plastic tanks (especially medium-density polyethylene). Know that there are different grades of polyethylene and not all are created equal. Some installers build concrete walls around them in an attempt to reduce pressure.

Fiberglass has reinforcement and is quite a bit stronger. You’ll find that the fiberglass septic tank warranties are better (some have 25-year warranties), but concrete, as previously mentioned, can last for decades. You should buy the best-quality tank you can afford, regardless of the material type, but this is an issue you should definitely discuss with your contractor before making a purchasing decision.

Septic Tank Installation Checklist for Homeowner

It always pays to do a little homework before hiring a contractor and be prepared with a list of questions when negotiating your work. Here are some considerations and questions to ask when you are planning to have a septic tank or system installed:

• Ask about the warranties on labor and on  the tanks.
• If possible, get multiple quotes because they will vary greatly.
• Ask about the longevity of tank types (concrete, polyethylene and fiberglass).
• Ask about the price differences for installing tanks made from different materials (see above).
• Ask about the best tank size and configuration for your waste requirements while factoring in the long-term cost of septic cleaning.
• Ask about septic tank riser options (see our other blog post) for your tank.
• Ask about timeline for completing job (no one wants to go without a toilet and water).
• Make sure your pro is licensed (if required) and insured (get copies) before working on your property.

A septic tank installation is never a welcome expense when it befalls a homeowner but know that taking the time to ask questions and educate yourself a bit can save you money, both in the short term and the long term. If you are having septic issues, check out our blog for troubleshooting tips and get free septic and plumbing quotes on our website.

*To keep your septic system in good shape, check out our tips on home plumbing maintenance on our 21 plumbing tips page.