Buying Vacant Land: Will You Need a Septic System?

A sewer connection could be key to making your land purchase a good place on which to build a house.

By , J.D. · UCLA School of Law

Found the perfect piece of land on which to build your dream home? Great! But unless you're content to use an outhouse, you'll want to find out whether a sewer system is available for the property, or whether you'll need to install one. The answer can affect not only your overall plans for the property, but your construction timeframe and budget. Here, we'll discuss how to research the details and protect your interests.

Is the Property Served by a Sewer?

Question one before buying a vacant plot of land is whether it is already served by a sewer. If not, you'll need a septic system. The easiest way to find out about sewer access is to ask the seller of the land or a real estate agent, if one is involved. If there's no one immediately available to ask, you can look for clues on your own.

If you know that municipal water is available on the property, chances are the property is also served by a sewer system. Sewer systems typically exist in areas of high population densities (due to the need to treat and dispose of large amounts of community wastewater). So, if the property is in a city, town, or a highly populated area, a public sewer system probably exists.

On the other hand, if the land must rely on a well for water, or if it's outside of city limits in a rural or less populated area, you'll probably need to install a septic system (which handles the waste water from your property only).

Also, if it's a large, multi-acre property, (for example, land suitable for a ranch or a farm), it will probably require its own septic system.

How Much Will It Cost to Connect to and Use an Existing Sewer System?

If the piece of property is served by a sewer system, things are pretty simple. Your main requirement as the land owner is to construct the connection from the new home to the main system. (In fact, you probably wouldn't be allowed to "go rogue" and construct your own septic, or alternative wastewater treatment system, even if you want to.)

An experienced general contractor or plumber should be able to give you an estimate of the time and expense involved in following through on this. Commonly, the cost is somewhat less than what's required to construct a conventional septic system (and much less than to construct an alternative septic system, described further below).

Additionally, you'll probably need to pay a connection fee to your sewer service provider (usually the same entity that also provides water service to the property). Once connected, the provider will charge a periodic sewer usage fee, most likely along with your monthly water bill. You can find out the amount charged for sewer connection fees and get an idea of monthly sewer service costs by inquiring with the service provider, the property's seller, or an involved real estate agent.

If a sewer system is available, local regulations might require you to pay the sewer connection fees before being issued a building permit. Typical regulations also require that a professional contractor or plumber install the connection.

If the Property Isn't Served by a Sewer: What Regulations Affect Your Building a Septic System?

If you must install a septic system (because no sewer system serves the land), this will require more time and expense. Because failing septics are a major source of water pollution (due to bacteria infiltrating nearby water supplies), almost all land is subject to state and local laws governing installation and maintenance of septic systems.

You will need to ensure that your installation complies with applicable laws. Step one is most likely to obtain a septic permit, probably from the county in which the land is located. A site evaluation is usually required before a septic permit can be issued. Most site evaluations must include a topography assessment, as well as a soils test (including a percolation or "perc" test). These can be completed by the local health department or a licensed site evaluator or engineering firm.

What Will the Site Evaluation Tell You?

The results of the site evaluation will determine whether you can build a conventional (gravity-fed) septic system or whether an alternative system will be required. Alternative septic systems are essentially modifications of conventional septic systems, specifically engineered to work with the soils and topography found on a particular property.

If the results of the site evaluation show that your land is unsuitable for a conventional septic system, an engineer or septic design professional must design an alternative system. For example, if the property has a high water table, a sand or mound system might be recommended and designed, or if soil permeability is an issue, a pump system might be an alternative.

Alternative systems can sometimes cost many times more than a conventional one. This is on top of the cost of hiring the professional to perform or review a site evaluation and draft the septic design.

Will You Have Enough Room Left for the Home?

Septic regulations also typically govern where on the property the septic system can be installed. Septic systems must be set back a certain distance from wells and other water sources, as well as from roads, driveways, buildings, other improvements, and property lines.

These restrictions can severely impact where you can build your home. You must ensure that there will be enough room to install the septic system in a suitable location, in addition to a well (if necessary), and still have room to build the home you desire in an acceptable location.

How Can You Protect Your Interests Within the Purchase Contract?

Since the results of a site evaluation can greatly impact the value of the property, it's wise to condition the purchase of any vacant land without sewer service on receiving an acceptable site evaluation. You'll want the ability to negotiate the purchase price, or even to cancel the contract, if the results of the site evaluation are unacceptable. An experienced real estate attorney should be able to assist you with creating such a contingency in your purchase contract.

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