When buying an acreage, you look at whether the home has enough bedrooms, square footage, lot size and overall fit for your family; and similarly the septic system needs enough capacity for your household’s water usage. A passing inspection lets you know how the system is functioning, but you also need to know how much household wastewater the tank, field and receiving soil can handle. This article explains how to make septic system wastewater processing capacity a part of the purchasing discussion.
Key takeaways
- Ask about capacity as well as condition. A system can have sound components, but be too small for the household moving in.
- Bedroom count-dependent water processing capacity isn’t relevant, if you have 10 college kids living in a 3-bedroom acreage. The family of five in the video needs a system that supports their wateruse. That’s it. You need to understand your household wateruse and if the system has the capacity to handle that.
- Look at the tank, field and soil together. Enough room in one part does not establish enough capacity throughout the system.
- Find out what was actually built. Today’s bedroom count may reflect renovations made long after a legacy septic system was installed.
- Include any work in your purchase plans. A clear assessment helps you compare maintenance, restoration and replacement before the property becomes your responsibility. Much like when you buy a home, where you expect to make renovations and make those financiang calculations, you need to understand if you will need to make changes to your septic system.
Consider the system alongside the home
When buying a home, you look at whether it fits your household and your family’s wants and needs. Does it have enough bedrooms and bathrooms? Does it have the amount of room and square footage you want? Does it have a big enough yard, enough garage space and a large enough kitchen?
The family of five in the video
In the video, a family of five purchases an acreage. The septic system is inspected before the sale and passes. They move in and use water normally for a household of their size. By the second year, the system starts showing signs of failure.
We see this situation fairly regularly. The family is understandably frustrated. They had the inspection done, they aren’t doing anything unusual, and now there is a wet area in the yard because of a system that isn’t keeping up.
The question we need to answer is whether the system has enough capacity for that household’s normal use, and whether its condition and operation allow it to use the capacity it has.
Knowing how many people lived there before helps us understand its history. What matters most is what the tank, field and soil can handle now. A change in ownership alone doesn’t diagnose the cause of a problem.
Understand what the inspection established
A septic inspection provides valuable information about the components examined, the conditions observed and the operation tested. The report should also make its scope clear. Ask whether it included a review of design capacity and how that relates to your household.
There is a practical difference between observing the system operate during an inspection and establishing how it will perform through normal household use and seasonal conditions. If the property has been vacant or lightly used, you most likely won’t see wet spots in the yard. If the system was recently pumped, make sure that is part of the record, too.
Design documents, permit records, maintenance history and the seller’s account of past problems help fill out that picture. EPA’s homebuyer guidance similarly emphasizes reviewing records and having the system assessed before purchase.
If a problem appears later, we go back to those facts. We don’t assume the inspection was wrong, or that the family must be using too much water. We establish what changed and what is limiting performance.
Start with the treatment capacity in the tank
At the tank, we need the working capacity available for primary treatment. In a common tank with a separate pump chamber, that pump chamber is not part of the settling capacity. A total tank size written on an old invoice may not give us the number we need.
Wastewater needs adequate space and time for solids to separate before the effluent continues toward the field. As flow increases through a fixed volume, its average residence time decreases. Sludge accumulation and damaged internal components can further affect separation.
In our tank-sizing video, I use a two-day volume example to explain that relationship. For a purchase assessment, we then compare the actual tank and household profile with the design information. We also check the divider, inlet and outlet arrangements, pump or siphon, controls and any filtration.
A sound tank with working equipment is a good start. We still need to establish whether it has enough treatment capacity for the household that will depend on it.
Look at the field and the soil beneath it
The treatment area has its own capacity. Its size, construction and receiving soil characteristics determine how much effluent it can accept and treat. A large yard does not automatically mean a large field, and a large field does not mean a large processing capacity.
Soil texture, structure, drainage and the depth of suitable soil all matter. So do the quality of the effluent and the way it is applied. The soil is doing treatment work as well as accepting water.
We also look at whether wastewater is reaching the available area properly. A blocked header, damaged line or distribution fault can concentrate flow in one part of the field while leaving another part underused. In that situation, restoring distribution may recover capacity already built into the system.
Where the receiving conditions themselves are limiting performance, the discussion changes. We may need to address incoming water, treatment quality, drainage or the size and design of the treatment area. Understanding the cause is what lets us compare sensible options.
Look beyond the bedroom count on the listing
Acreage homes change over time. Basements are finished, bedrooms and bathrooms are added, and water-treatment equipment is installed. The septic system outside may still be the one that served the original home.
Design standards have changed over the decades, too. We look for what the system was designed to do and what was actually installed. Today’s room count is useful, but it cannot confirm yesterday’s construction.
Your own plans matter just as much. Tell us if relatives will stay for extended periods, if you intend to add a suite, or if a whole-home water-treatment system will discharge to the tank. It is much easier to include that information before you buy than to discover its effect after you move in.
Questions to bring to your purchase
- What daily wastewater volume was the system designed to handle, and are the design and installation records available?
- What is the tank’s primary treatment working capacity, separate from its pump or dose chamber?
- Where is the field, how large is it, and what do the records tell us about the receiving soil?
- What did the inspection establish about delivery, distribution and field response?
- Have changes to the home, occupancy or water-treatment equipment affected the expected wastewater load?
- Does the system fit our household’s intended use, and what work or ongoing costs should we include in our plans?
You don’t need to answer these yourself. They are questions to bring to your Realtor, seller and septic professional so the right information becomes part of your decision.
Give yourself room to make the decision
A septic concern doesn’t have to end an acreage purchase. It needs a clear explanation and, where work is required, a scope and cost that everyone can understand.
There may be plenty of capacity. There may be capacity that can be restored through repairs or treatment improvements. Or the property may need a larger change to support your plans. We explain those options and their costs and benefits so you can decide whether the property still makes sense for you.
You’ve already thought about whether the kitchen, bedrooms and yard will work for your family. Give the wastewater system the same consideration. It supports everyday life in that home, and you should understand how well it fits before it becomes your responsibility.
Buying or selling an acreage? We’re happy to speak with you and your Realtor about the system, the household it needs to support and any work that should be part of the purchase plans. Book an Assessment to better understand your septic system before making a decision.