Buying a House With a Septic Tank: Is It a Bad Idea?

What is a septic tank? | How they work | Septic tank types | Septic vs. sewer | Before you buy | Maintenance | Costs | Should you buy? | FAQs

If you’re used to the convenience of living in a house connected to a public sewer line, buying a house with a private septic tank might seem like a bad idea. But it doesn’t have to be — as long as you know what you’re getting into.

When you own a property with a septic tank, you’ll be 100% responsible for the maintenance vs. having your utility company take care of it for you.

You'll also have to follow the dos and don’ts of living on a septic system. This includes a long list of items you should never put down the drain.

Finally, you'll have to deal with the idea of human waste hanging out in a tank on your property. (Some people are just grossed out by that.)

However, owning a septic tank actually comes with some surprising benefits — including no monthly sewer bill, a smaller environmental footprint, and the freedom to build just about anywhere.

And, if you live in a rural area, having a septic tank is pretty much a fact of life.

To learn whether buying a house with a septic tank is right for you, consider the following before purchasing one:

• The type of system
• It’s age and condition
• The kind of maintenance required
• The potential costs of upkeep, repair, and replacement

What is a septic tank?

A septic tank is an underground chamber designed to receive and partially treat wastewater from household plumbing. Wastewater includes "black water" from toilets and "gray water" from sinks, showers, and washing machines.

First developed in the 1860s, septic tanks use a combination of technology and naturally occurring processes to contain, separate, break down, and filter the various waste products that enter into it. They're designed to hold on to solid waste and return treated water to the soil.

How does a septic tank work?

In a conventional septic tank system, sewage and other wastewater flows from the house into the underground septic tank through a septic line or "inlet baffle."

Heavy solids sink to the bottom, forming what’s called the "sludge layer." Grease, oils, and lighter solids rise to the top, forming what’s called a "scum layer."

As more liquid enters in, the middle layer of wastewater ("effluent") is pushed into a secondary filtering compartment. From there, it flows through the "outlet baffle" into what’s called a "drain field" (or "leach field"), where it's gradually dispersed through porous pipes into underground trenches surrounded with gravel.

The inlet and outlet baffles are strategically positioned between the bottom layer of sludge and top layer of scum so that only the middle layer of effluent flows out. Solids stay in the tank, where they're broken down by naturally occurring bacteria.

As the wastewater enters the drain field and percolates through the ground beneath, microbes in the soil continue to treat it — filtering out bacteria, viruses, and other contaminants before the effluent reaches the underlying groundwater.

Types of septic tanks

Over the years, manufacturers have come up with variations on the conventional septic tank to account for different soil conditions and terrains.

For example, a property with poor soil conditions or a high water table at risk of contamination may require an alternative septic system with additional disinfecting capabilities, more controlled effluent dispersal, or pumps designed to move wastewater away instead of absorbing it into the nearby drain field.

One of the more advanced septic system types, the aerobic system, pumps oxygen into the septic tank to stimulate bacterial activity for additional cleansing and reduction of pathogens in the effluent.

While great at filtering wastewater, these are pricier than conventional systems and require additional maintenance. Pumps on these systems usually need to be replaced every 10-12 years.

Chamber and drip distribution systems incorporate a secondary distribution chamber or pump tank for more controlled dispersal of effluent through long, tunnel-like chambers or a network of tubing buried beneath the top layer of soil.

Mound, sand filter, and constructed wetland systems pump effluent through either engineered mounds or additional compartments containing layers of sand, gravel, and/or nutrient-rich flora. They're particularly useful in areas with high groundwater levels or insufficient soil.

Evapotranspiration systems are sometimes preferred in warm, dry climates. They replace the traditional drain field with an open air tank filled with sand and water, which capture and treat the effluent until it evaporates into the air.

In some places, you can even find communal septic systems that collect and treat water from multiple properties. These are most commonly found in rural subdivisions where no centralized sewer exists.

Which type of septic system is best?

The type of septic system you need depends on:

• The size and terrain of your property
• The depth and quality of the soil
• The number of people in your household
• Local regulations governing septic systems

Properties with sloping terrain or poor soil quality may require an alternative system incorporating an aeration pump or a modified drain field.

Each septic system design has unique benefits, but advanced systems with more complex technology will require additional upkeep.

Before buying a house with a septic tank, you want to know the type you’re dealing with and the maintenance required to keep it in good condition.

In most states, sellers are required to disclose details about the type of sewer system they operate on as well as any known issues.

If you’re working with a real estate agent to buy a home, they'll be able to request this information from the seller on your behalf. They can also recommend an inspector to check the condition of the system and offer recommendations on how to maintain it.

Septic tank vs. sewer: pros and cons

Freedom to live where you like (coupled with more personal responsible)

Septic systems can be installed wherever there's enough land and suitable soil to accommodate them. If you’re willing to take on the responsibility of maintaining one, a septic tank gives you the freedom to live just about anywhere.

👉 The catch

With a septic system, you’re essentially accepting ownership of your own wastewater treatment, whereas a public sewer system takes care of it for you. You can simply flush your toilet and forget about it — that is, for a fee.

Lower overall costs (until you need to replace it)

Between piping installation, connection fees, and permitting, it can cost as much as $30,000 to transition a property to a public sewer line.

There are also monthly sewer bills to consider. Among the 50 largest cities in the U.S., average monthly sewer charges run anywhere from $34 (for 3,500 gallons of water consumed) to $135 (for $15,000 of water consumed).[1]

Households that rely on the municipal sewer may also be required to foot the bill for costly improvement projects through periodic rate hikes or "sewer betterment fees" assessed to property owners in newly sewered areas. In some places, these can run as high as $20,000.

Once installed, septic tanks are surprisingly affordable to maintain. Septic system pumping costs $300-550 every 3-5 years — averaging out to $5-15 per month.

👉 The catch

When your system does need to be replaced, the typical price range for a new tank is $3,178–10,486, according to HomeAdvisor.

No unpredictable rate hikes (but a lot more care with what goes down the drain)

Septic systems free you from monthly usage bills and betterment fees for improvement projects.

👉 The catch

Septic systems can be finicky. You have to be extra cautious with what you put into your pipes to avoid clogs and backups.

Septic tanks are designed to partially treat household wastewater from bathrooms, kitchens, and laundry facilities. They’re NOT designed to act as a solid waste receptacle or industrial filtration system.

Chemicals — like those found in commercial cleaning products — can diminish the bacteria septic systems rely on to break down and cleanse wastewater.

The use of a garbage disposal with a septic system is also questionable, since it can cause a tank to fill up much faster (requiring more frequent pumping).

With a septic tank, you also need to be mindful of your water consumption, since a large influx of liquid into the tank can cause it to overflow before waste solids have had the chance to separate from the effluent.

Still, the potential downside of owning a home with a septic tank is greatly reduced when the system is properly maintained.

Less environmental impact (but only when properly maintained)

When septic systems work as they should, they take up very little in the way of public resources. They may even have a net positive impact on the environment.

Recycled water from septic tanks can replenish the local groundwater supply relying largely on biological processes and gravity.

By contrast, public sewer systems require a lot of energy to pump wastewater to centralized wastewater treatment facilities.

While wastewater plants must adhere to EPA standards, they may not always sufficiently rid the effluent of pollutants before releasing it into local waterways.

Often, recycled wastewater contains elevated levels of nitrogen (from industry and agriculture) and phosphorus (from sewage), contributing to water pollution and the destruction of plant and animal life.[2]

Public sewer lines can also clog and back up into household plumbing or overflow into streets, elevating public health risk by releasing all sorts of nasty pollutants and pathogens into the environment.

👉 The catch

Poor maintenance can result in septic system failure, increasing the risk of groundwater and soil contamination. This is especially dangerous if you're near a source of public drinking water.

Common causes of septic system failure include backups, ruptured pipes, or the sludge layer piling up so high within the tank that it begins to exit with the effluent.

Long lasting (but subject to local maintenance and replacement rules)

When kept in good working order, septic tanks can last 40 years or more. But that doesn’t mean you can just install one and forget about it.

👉 The catch

The EPA issues voluntary national guidelines governing onsite or decentralized wastewater systems (i.e., septic tanks).[3] However, the legal authority for regulating onsite wastewater treatment systems generally rests with state, tribal, and local governments.

Depending on where you live, your state or county may require that you have your septic tank pumped at specified intervals — usually every five years or less.

Some state and local authorities also require what’s called a "Time of Transfer Inspection" before a property with a septic tank can be sold. This is to eliminate sub-par or polluting septic systems. In these areas, it's actually illegal to sell a house with a failing septic tank. If you want to sell, you're going to have to fix it.

Additionally, since septic tanks are sized according to the number of bedrooms in a house, your municipality may also require you to modify or replace your septic system if you want to add square footage to your home at a later date.

Advice before buying a house with a septic tank

If you’re interested in a home with a septic tank, the best thing you can do is get informed about:

• How it works
• The shape it's in
• The type of maintenance it will require
• Local ordinances around septic system installation and upkeep

Start with a septic system inspection

Even if you live in a state that doesn’t require a "Time of Transfer Inspection," you’ll want to order a thorough, professional inspection before you buy a home with a septic tank. The cost of a septic system inspection ranges from $250-500.

» JUMP TO: Septic tank costs

Depending on where you live, it may be up to the seller to foot the bill. Ask your real estate agent about whose financial responsibility it is to cover septic inspections in your state.

A pre-sale septic system inspection will usually check for:

• Proper flow of wastewater from household plumbing to the tank
• The location of the tank and drain field
• The size of the tank in relation to the home it serves
• The depth of the sludge and scum layers
• The condition of the tank, lids, piping, baffles, and distribution box leading to the drain field
• Surface water or oversaturation of the drain field

Local code dictates how far a septic tank and absorption field should be set back from other property and environmental features, such as:

• Your house’s foundation (usually 5-15 feet),
• Neighboring property lines (usually 10 feet),
• Private wells (usually 100 feet),
• Public water sources (usually 300 feet).[4]

However, on older properties, septic systems weren’t always installed up to modern code.

If the home is on a well, you may want to have the water tested for signs of sewage contamination. Your city or county may provide free or low-cost water testing.

The cost of any needed repairs usually falls to the seller. However, this ultimately depends on the conditions of the purchase contract and the outcome of negotiations during your contingency period.

Ask the seller for maintenance records

Before you pull the trigger on a home with a septic tank, you’ll want to know that it’s in good working order. A neglected septic tank can cause a range of issues, including soil and groundwater contamination.

Ask the sellers for records of recent maintenance, including the last time it was pumped and inspected. As a buyer, you can also request that the seller have the tank emptied before you move in.

An experienced real estate agent can advise you on the best strategy for negotiating these types of conditions, known as contingencies, into a purchase offer.

Know what kind of maintenance your septic tank requires

Septic systems vary in the type and frequency of maintenance required.

More advanced systems, such as aerobic systems or those that use a pump to help usher the effluent to the drain field, tend to require more attention than conventional systems that rely on biological processes and gravity to do the work.

Advanced septic systems also have additional parts (like an aeration pump) that may need to be replaced from time to time.

As you may have guessed, more frequent inspections and maintenance will require deeper pockets to cover the associated costs.

Knowing what type of septic system you have will give you an idea of what will be expected of you as the future homeowner.

Get familiar with local septic system regulations

The EPA recommends you have your septic tank inspected every three years and pumped every 3-5 years. However, states and counties have the authority to enforce stricter maintenance standards.

Find out more about local septic system regulations by doing a Google search of "(your county) septic system requirements."

In addition to mandating how often you need to service your septic system, local authorities may require inspections and extra permitting for any construction or repairs that could potentially affect your septic system.

If you want to add bedrooms or additional plumbing to your house, you'll likely be required to get a bigger tank to accommodate more people.

Additionally, many municipalities require a septic tank inspection before a property can change hands. If your septic tank is in poor shape, you may be on the hook for replacing it before you sell. In lots of places, it’s illegal to sell a home with a failing septic system.

When in doubt, get in touch with a local realtor, who should be able to advise you on local septic system rules and restrictions.

How to take care of your septic tank

Responsible septic tank ownership requires careful diligence to keep it in good working order.

In addition to regular inspections and pumping (recommended every three years or so), you’ll need to be more mindful about your daily usage about what you flush through the pipes and steer clear of the tank and drain field.

Careful what you flush through your pipes

Since a septic tank relies on biological processes to break down waste, ideally everything that goes into the tank should be biodegradable. However, septic tanks can also accept reasonable quantities of detergents and soaps from typical household laundry, sink, and shower use.

Items to avoid putting into your septic tank

Think twice about using a garbage disposal when you own a septic tank. This can add significantly more solid waste to your tank, requiring more frequent pumping.

Additionally, use commercial cleaners, laundry detergents, and chemicals in moderation. These can cause suds and clog the system. They’re also not as easily broken down by bacteria. As an alternative, try using more mild detergents, vinegar, or baking soda instead.

To avoid overloading your tank, monitor the amount of wastewater that enters your system at one time. Otherwise, you risk effluent leaving the system before it’s been properly treated — or worse, the system backing up into your indoor plumbing.

To avoid the risk of flooding your tank, fix leaky faucets and toilets right away. Also, spread your laundry across the week so you do no more than one or two loads per day. A single load of laundry can pump 40+ gallons of water through your septic system.[5]

Low-flow fixtures and appliances can also help you limit the amount of water that gets flushed through your tank on a daily basis.

Keep your distance from the tank and drain field

To avoid structural damage to your septic system — or potential harm to your health — steer clear of the tank and drain field.

If you’re not quite sure where the tank is located, you may be able to spot it by looking for the tank lids or following the direction of the 4-inch sewer pipe leading from your basement. Generally, the tank will be 5–25 feet from your house.

Heavy objects can break pipes and compact soil, cutting off the oxygen flow required for bacteria to filter the effluent that drains into the soil.

Therefore, it’s best to avoid driving over or building anything on top of the drain field. (While not always the case, you can often spot the absorption field by the exceptionally green grass growing on top of it.)

Likewise, you’ll want to divert surface water from sprinklers, hoses, and gutters away from the drain field. Too much water can cause it to overflow, turning your yard into a swampy mess.

While it should go without saying, you want to avoid breathing in the fumes from a septic tank. Septic tanks are built to be waterproof and airtight but, if you linger over an open tank lid without proper protection, the noxious fumes can quickly cause breathing difficulties and asphyxiation.

Keep the tank lids on tight and let professionals deal with any inspections.

Finally, choose a spot other than the septic tank area to grow a garden or plant a tree whose roots might damage the piping underneath. Apart from protecting the leach field from potential damage, you also avoid any risk of contaminants being absorbed into your edibles through the soil.

Keep up with maintenance and inspections

Failure to maintain your septic tank could lead to plumbing issues, soil contamination, and even contamination of groundwater that feeds into the local drinking water supply.

As a rule, tanks should be pumped when they are one-third or more of the way filled with solids, the scum later is within six inches of the outlet baffle, or the sludge layer is within 12 inches of the outlet baffle.

Exactly when a septic tank reaches its pumping threshold largely depends on tank size, the number of people in the household, and the wastewater output

Every 3-5 years is typical.

The only way to know for sure whether a tank is ready to be emptied is to have it inspected — preferably every 1-3 years to be on the safe side.

When you do have your tank serviced, keep the record on hand. Having proof of regular maintenance can go a long way with prospective buyers when it comes time to sell.

Septic tank costs

Septic tank costs can be broken down into three categories:

• Inspections
• Maintenance and repairs
• Installation and replacement

Septic tank inspection costs

Prior to a home sale, a complete septic tank inspection will cost $250-500.

A sewer line inspection, which involves the use of a camera scope, can tack on an additional $250-900 to the inspection price.

Maintenance inspections, recommended every 1-3 years, average $100-150.

Septic system maintenance and repair costs

Maintenance, in the form of having your septic tank pumped and emptied of sludge, will run you $250-500 every 1-5 years, depending on how quickly you fill it.

As a rule, you should have your tank emptied whenever the sludge layer reaches about ⅓ of the tank’s height capacity.

Annual maintenance inspections to check the tank and sludge levels will run you another $150.

If your drain field is showing signs of poor drainage, you may need to pay $1,000-2,000 to have it aerated. The process uses pressurized air to break up compacted soil, allowing freer movement and thus better filtering of wastewater. While not cheap, it’s far less expensive than digging a new drain field.

Repair and replacement costs depend on the parts and labor involved.

Some of the more common parts that might require replacement include baffles (inlet/outlet pipes), aerobic system aeration pumps, effluent filters, and tank lids.

Septic tank installation and replacement costs

To install a conventional septic system and leach field, the typical price tag is $2,000-10,000.

Costs to install a more advanced aerobic system range $8,000-20,000 — possibly more if your property requires an especially big tank or alternative system with a specialized drain field.

A soil test to determine the suitability of the soil (and type of drain field needed) adds an additional $750-1,300 to the final bill.

Actual installation costs vary by location, system type, tank size and material, and the amount of labor involved. Concrete septic tanks, the most common and durable type, average $700-2,000. Lightweight alternatives like fiberglass, plastic, and steel run $500-2,500.

A well-maintained septic tank can last 20-40 years, but it will eventually need to be replaced.

Replacement costs are similar to installation costs, but with the added expense of removing and disposing of the prior septic tank — which comes out to about $5,500.

Converting an existing conventional septic system to a more efficient aerobic system ranges from $5,000-10,000.

Septic tank installation and replacement cost breakdown

Bottom line: Should you buy a house with a septic tank?

In many cases, owning a septic tank is more practical for those who want to live remotely since access to a sewer line may be limited.

Apart from lower installation costs compared to remote sewer line hookup, septic tanks can save you money over a regular monthly sewer bill — not to mention the sewer betterment fees charged by municipalities.

Septic tanks are arguably more environmentally friendly, since they eliminate waste, recycle water, and naturally replenish water tables using naturally occurring processes.

A septic tank, however, needs to be properly maintained or you could have a costly mess on your hands. There could also be broader environmental consequences like groundwater contamination.

With a septic tank, you’ll need to be careful what you put down the drain and how much water you pump into it on a daily basis, as you could risk clogging or flooding the system.

Septic tank FAQs

Related reading

How Much Does a Septic Tank Inspection Cost?

Wondering how much a septic tank inspection costs? We have the answers!