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What is a septic system?


If you are building a home or a building you will most likely be in need of septic solutions. A home or building will generally use one of two different strategies for wastewater treatment. The first option is a citywide wastewater treatment plant. This kind of system is connected to dozens of homes and buildings, usually throughout an urban area, by way of central sewer systems. Wastewater is carried from the building into the sewers and from the sewers to the plant, where it can be treated and released. A septic system is the second option for wastewater treatment. Septic systems are self-contained systems that can perform the entire wastewater treatment process on their own, without the need for a treatment plant. Unlike wastewater treatment plants, which collect and treat the wastewater from hundreds or thousands of homes and buildings in each geographical area, septic tanks are linked to only one home or building. They are responsible for collecting and treating all the wastewater produced in that one building. Septic systems have two components: the septic tank and the leach field. The septic tank collects the wastewater. In the case of a residential septic system, pipes would run from the house to the septic tank, carrying wastewater from toilets, bathtubs, sinks, and other drains in the house. In addition to the collection of the wastewater, the septic tank’s primary job is to separate liquid-solids and sludge from the water. This process doesn’t require any mechanical components and is instead dependent entirely on density. Materials that are less dense than water, such as oil and grease scum, float to the top of the septic tank. Materials that are denser than water sink to the bottom, forming a layer of sludge. The remaining layer is clarified wastewater: it isn’t adequately treated or purified but has been rid of much of its waste and debris. The leach field is used to drain water out of the septic tank once it has been clarified. The leach field is precisely what it sounds like: a field, usually in the backyard of a property, where there is enough space for the septic tank to be buried and drained. The septic system distributes the cleansed wastewater evenly throughout the field using a series of perforated pipes, and the processed water then flows through the ground. Slowly, the soil and sand of the leach field absorb the water and filter out its remaining contaminants. As long as the leach field is planned correctly, the septic tank should be able to drain regularly without posing any risk to nearby ecosystems. The other waste—the liquid-solids (or scum) and the sludge continue to sit in the septic tank itself. Ideally, these components break down naturally. In some cases, particularly if the septic tank is small, it will need to be pumped periodically to remove the waste and clear out space for new wastewater.

Types of Septic Systems

There are many different types of septic systems that have different benefits and situations they should be used in. Below you can find a list of these systems and septic solutions:

Conventional Septic System aka Standard Septic System

Conventional septic systems are the simplest and most affordable septic systems on the market. As such, they remain the norm for most residential properties, if the soil allows it. Like most septic systems, a conventional system has two primary components: the tank and the leach field. Learn more about conventional septic systems

Mound Systems

A mound septic system is an alternative septic solution to the traditional leach and drainage fields used in most septic systems. A mound system is used when the soil conditions of a drainage field are not conducive to wastewater treatment and draining. Learn more about mound systems.

Drip System aka Sub Surface Drip Irrigation

Drip systems or SDI systems were originally designed for farm irrigation, and are still frequently used for watering permanent crops. A drip septic system uses the same method to disperse treated wastewater to the soil. This septic system provides an engineer solution to some of the septic complication landowners can encounter. Learn more about drip septic systems.

Greywater System

A greywater system is a type of septic system that diverts some wastewater away from the septic tank and uses it to irrigate lawns, gardens, or other landscape features. Greywater systems are commonly used in California to irrigate landscaping by using water that would otherwise be wasted instead of paying for additional water. Learn more about greywater systems.


In onsite wastewater treatment, “cesspool” refers to an older method of disposal, not typically used for new development. Most municipalities or governing agencies will not permit such system types. However, cesspools still exist on some properties to dispose of wastewater. Learn more about cesspool systems

Pressure Distribution System

Pressure distribution septic systems solve many of the inherent problems and weaknesses of gravity distribution systems. As their name suggests, pressure distribution systems use pressure to ensure that effluent is evenly distributed throughout a soil distribution area. In situations where the leach field is located upslope from the septic tank, a pressure system can transport the water uphill through the pipes and into the proper distribution area. Pressure distribution systems also help prevent saturation of leach field soils by promoting more even dosing throughout the field. Learn more about pressure distribution systems.

At-Grade System

Learn more about at-grade systems.

Filled Land System

Learn more about filled land systems.

Shallow Sloping System

Learn more about shallow sloping systems.

Seepage Pit

Learn more about seepage pits.

Sand Filter

Learn more about sand filter septic systems.

Pre-treatment Device / Advanced Treatment Unit

Learn more about pre-treatment devices and advance treatment units.

Composting Toilet

Learn more about composting toilets.

Incinerator Toilet

Learn more about incinerator toilets.

Above Ground System

Learn more about above ground systems.

Non-Standard Experimental System

Learn more about non-standard experimental systems.

Non-Standard Alternative System

Learn more about non-standard alternative systems.

Onsite Wastewater Treatment System (OWTS)

Learn more about onsite wastewater treatment systems.

Why do I need a septic system?

Every property needs to have detailed plans for how it will handle wastewater. If you are building a house. It’s essential to think about what will happen to wastewater—from bathwater to dirty dishwater to human waste—when it goes down the drain or gets flushed down the toilet. Your home must either be connected to a central sewer system, to make use of the city wastewater treatment plant, or have its own septic tank. Either option will allow the safe disposal of wastewater from your home and ensure that contaminated water, scum, and sludge are not spilling out into water streams or other fragile environment ecosystems. A good septic tank or sewer connection will also prevent sewage backups in your drains. Unlike a bad septic tank or sewer connection which can lead to smelly, hard-to-fix plumbing issues that can pose serious health risks. In short, having well-planned septic solutions for disposing of wastewater will mean less maintenance and lower cost, the obvious preference of any home or business owner.

When do I need a septic system?

Above, we answered why wastewater disposal and treatment systems are so important. However, why should you have a septic tank when you could just connect your home or business to your city’s central sewer system? In most cases, central sewer systems and city water treatment plants are the primary strategy for wastewater treatment in urban areas. Rural areas, meanwhile, are more likely to use private septic tanks. There are several reasons for this divide. In urban areas, there often just isn’t enough property space to bury a septic tank and set up a safe, environmentally responsible leach field. Those properties are located in such a way that they can be connected to their city’s central sewer system at low cost due to proximity. In rural areas, there is more property space, which means that there is room to have septic tanks and leach fields. Many rural areas—and some suburban areas are also not served by the central sewer system at all. And even if the central sewer system does serve your area, it can sometimes cost more to connect your home to it than if you were to install a private septic system.

Who designs a septic system?

Septic system design is about more than burying a septic tank in a field and hoping for the best. Indeed, proper septic system design is a complex process that considers various environmental and engineering factors. As a result, it’s important to hire a skilled and qualified civil engineering team or a qualified professional to spearhead the design of your septic system. At Hogan Land Services, septic system design is one of the specialties of our civil engineering department. We can perform all the necessary, legally-mandated tests to make sure that your leach field is an appropriate site for wastewater disposal. These tests—including preliminary soil explorations, pre-perc site evaluations, and percolation tests—are mainly designed to assess the absorption rate and permeability of the soils in your leach field. The soil must be able to absorb water at a specific rate to be an environmentally safe location to drain clarified wastewater. Another assessment, the wet weather groundwater test, is key to making sure that your septic system can perform adequately in torrential rains. Rain can affect the permeability of the soil and cause septic tank overflows, among other risks. If your leach field site passes all the key tests, Hogan Land Services can continue with the rest of the septic system design process. From designing a septic tank that is appropriate for your building and the amount of wastewater it is likely to generate to septic construction services, our engineering team can handle the full range of septic system design.

How much does a septic system cost?

Because septic system planning is such an involved process—including tank design, leach field planning, soil testing, and septic system construction—costs can be hard to predict. How much you will pay for your septic system will depend on numerous factors, including your location, how much wastewater your home or building produces, and whether a piece of your property is already suitable for use as a leach field. If you look at average septic system costs, you will still see a relatively wide range of different prices. For instance, Zillow reports that the average septic system—a system for a three-bedroom house on a property with quality soils—will run the range from $1,500 to $4,000. HomeAdvisor, meanwhile, puts the national average closer to $5,000, with the “typical range” falling between $2,700 and $7,600. These two reports create a very substantial “fair game” range for what you might expect to pay. At Hogan Land Services, we know that it can be difficult to plan for the expense of a septic system design and installation. If you want a more definite figure for expected costs, just give us a call. Our civil engineering team will be happy to consult with you about your property and your septic system design and give you an educated price quotation to keep in mind for your project budget.

What is a Septic System repair plan?

Unfortunately, septic systems do fail from time to time. You might wake up one morning to find that your drains are backed up with raw sewage, or that your leach field is soggy and smelly. Multiple issues can cause these problems, the most common of which is an overflowing tank. If you don’t pump your septic system frequently enough, then it might become overloaded with scum and sludge, leaving little room for wastewater and causing overflow issues. There’s also a possibility that the pipe that carries wastewater from your home to the septic tank is blocked. And in some cases, even your leach field can fail, due to the soil becoming incapable of absorbing wastewater for one reason or another.

⟶ Learn more about keeping your septic system up and running.

If your septic system fails, call Hogan Land Services immediately. We can assess your site and recommend the best and most cost-effective septic solutions. In some cases, that will mean merely pumping the septic tank. In other situations, it might involve repairing or replacing individual components of the septic system design. In scenarios where the leach field fails, you might need to relocate the septic tank to a different location entirely. In any event, Hogan Land Services can help you put together a repair plan to get your septic system back up and running. Should you have any questions about our septic services—including pricing information, repair plans, and more—please feel free to contact Hogan Land Services directly. You can reach us by calling 877-544-2104.