Above-ground septic tanks are legal in some places and banned in others—it depends entirely on your county or municipality, not on state or federal law

Whether you can install an above-ground septic tank comes down to local code, not a blanket yes or no. Some counties allow them with conditions. Others prohibit them outright. A few permit them only in specific situations—for example, when the water table is too high to dig, or when you're replacing a failed system and the soil won't support a traditional buried tank.

The reason for the variation is that septic regulation belongs to your local health department or environmental office, not to the state or federal government. The same county that bans above-ground tanks might be next to one that permits them. Before you buy a tank, contact your local health department or code enforcement office and ask directly: "Are above-ground septic tanks permitted in my jurisdiction?" They will tell you yes, no, or yes with conditions.

Key Takeaways

  • Above-ground septic tank legality is set by your county or city code, and rules vary widely even between neighboring jurisdictions.
  • Your local health department or code enforcement office is the only source that can tell you whether above-ground tanks are permitted where you live.
  • Some areas allow above-ground tanks only when soil conditions make burial impossible or when replacing a failed system.
  • Installing a tank without checking local code first can result in a citation, an order to remove it, or a failed inspection when you sell.

Why local code matters more than you might think

Septic systems treat household wastewater before it enters the ground. An above-ground tank sits on top of the soil instead of buried below it. The concern for most health departments is not the tank itself, but what happens around it: drainage, groundwater protection, setback distances from wells and property lines, and visibility.

A buried tank is out of sight and typically sits in a location where the soil naturally filters water. An above-ground tank is visible, requires a different drainage design, and may not integrate as well with the surrounding landscape. Some jurisdictions see this as a legitimate concern for public health or aesthetics. Others have decided the concern is manageable and allow them. There is no universal standard.

How to find out what your local code says

Start by calling your county health department's septic or environmental health division. Have your address ready. Ask: "Are above-ground septic tanks permitted in my area?" If they say no, ask whether there are exceptions—for instance, if your property has a high water table or poor soil. If they say yes, ask what conditions explore: setback distances from property lines, well distances, tank size limits, or design requirements.

If your health department directs you to code, you can also search your county's online code database. Look for sections on "septic systems," "wastewater treatment," or "on-site sewage." The language will be technical, but the permit or prohibition is usually stated plainly. If you cannot find it online or understand what you read, the health department staff can walk you through it by phone.

Keep a record of what you learn. Write down the name of the person you spoke with, the date, and what they told you. If you later need to install a system or defend a decision to a buyer or inspector, that documentation protects you.

What happens if you install one without permission

If your jurisdiction prohibits above-ground tanks and you install one anyway, code enforcement can issue a citation and order you to remove it or convert it to a buried system. The cost to remove and replace a tank is substantial—often several thousand dollars. You may also face fines.

If you sell the property, a home inspector or the buyer's lender may flag the tank as non-compliant. This can delay closing, reduce the sale price, or kill the deal entirely. Some lenders will not finance a property with an unpermitted septic system. It is far cheaper and simpler to check the code before you buy or install.

Situations where above-ground tanks are sometimes permitted

Even in jurisdictions that generally prohibit above-ground tanks, exceptions sometimes exist. The most common is a high water table—when the soil is too wet to safely bury a tank. Another is soil that fails a percolation test, meaning water drains too slowly or too quickly for a standard buried system. In these cases, an above-ground tank with a different drainage design may be the only option.

Some areas also allow above-ground tanks when you are replacing a failed system and the original location cannot be reused. If you are in this situation, your septic contractor will know the local rules and can guide you through the permitting process. Do not assume your contractor will handle the legal check—ask them directly whether they have confirmed with the health department that an above-ground tank is permitted for your specific property.

What to ask your septic contractor

If you hire a contractor to design or install a septic system, ask them to confirm in writing that an above-ground tank (if that is what you want) is permitted in your jurisdiction and for your property. A reputable contractor will have already checked local code and will know whether your soil, water table, and setback distances allow it.

If a contractor tells you "nobody will know" or "we can work around it," that is a red flag. Walk away. A licensed septic contractor is responsible for following local code, and if the system fails inspection or is discovered later, you are the one who pays the penalty, not them.

Frequently Asked Questions

Can I install an above-ground septic tank if my property has a high water table?

Possibly. A high water table is one of the few situations where some jurisdictions permit above-ground tanks, because burying a tank in wet soil creates safety and performance problems. Contact your local health department and describe your water table depth. They will tell you whether an above-ground system is an option and what design requirements explore.

What is the difference between an above-ground tank and a mound system?

An above-ground tank sits on the surface with the drain field below or beside it. A mound system is a raised drain field (the part that filters water into the soil) built on top of the ground, usually with a buried tank. Mound systems are more commonly permitted than above-ground tanks because they address specific soil problems. Ask your health department which option is allowed for your property.

If my neighbor has an above-ground septic tank, can I install one too?

Not necessarily. Your neighbor may live in a different jurisdiction, or they may have installed theirs before a code change, or they may have a specific exemption (like a high water table) that does not explore to you. Always check your own local code rather than assuming a neighbor's system is legal for your property.

Do I need a permit to install an above-ground septic tank?

If your jurisdiction permits above-ground tanks, yes—you will need a permit from your health department or code enforcement office. The permit process includes a site evaluation, design review, and inspection after installation. Never install a septic system without a permit, even if you believe the code allows it.

What should I do if code enforcement says my above-ground tank is illegal?

Ask for the specific code section that prohibits it and whether any exceptions explore to your property. Request a written explanation. If you believe there is an error or that your situation qualifies for an exception, ask about the variance or appeal process. Some jurisdictions allow variances when hardship or unusual site conditions exist. Your septic contractor or a local engineer can help you make that case.