Septic Tank vs Holding Tank
How to Choose the Right Wastewater Tank for Your Property
Septic tank or holding tank? They sound alike and both deal with household wastewater, but they work in completely different ways, and choosing the wrong one is a costly mistake. Here is the difference between a septic tank and a holding tank, and how to tell which one your property needs.
In short: a septic tank treats wastewater on site and releases the liquid to a drain field, so it runs continuously and only needs pumping every few years. A holding tank is fully sealed with no outlet, storing all wastewater until it is pumped out, which happens far more often.
What is a septic tank?
A septic tank is the first stage of an on-site treatment system. Wastewater flows in, solids settle to the bottom as sludge, and naturally occurring bacteria begin breaking them down. The clarified liquid, called effluent, flows out to a drain field where the soil filters it. Because the system treats and disposes of water continuously, the tank only needs pumping every few years to clear accumulated sludge. What it does require is suitable soil and enough space for the drain field.
What is a holding tank?
A holding tank does no treatment at all. It is a sealed tank with no outlet that simply stores everything that goes down the drain until a truck pumps it out. Because nothing leaves on its own, it fills steadily and needs pumping far more often, sometimes monthly, depending on size and use. The trade-off is flexibility: a holding tank works almost anywhere, including sites where poor soil, a high water table, or a small lot rule out a drain field.
Septic tank vs holding tank at a glance
Septic tank
- Treats wastewater on site
- Needs a drain field and suitable soil
- Pumped every few years
- Lower ongoing cost
Holding tank
- Stores wastewater, no treatment
- No drain field needed
- Pumped often as it fills
- Works almost anywhere
Which one do you need?
For most permanent rural homes with room and suitable soil, a septic system is the standard choice and the cheaper one over time. A holding tank makes sense when a drain field is not possible or not permitted, for a seasonal cabin, or as a temporary solution. Once you know which way you are leaning, our standard septic tanks and heavy-duty septic tanks cover most homes, with fiberglass options where code allows, and sealed holding-tank versions in the same range. Not sure on size? Our septic tank sizing calculator gives you a starting point.
Septic vs holding tank FAQs
Is a holding tank cheaper than a septic system?
A holding tank usually costs less to install because there is no drain field, but it costs more to run, since it has to be pumped frequently. Over the years, a septic system is typically the cheaper option where your site can support one.
How often does a holding tank need pumping?
It depends on the tank size and how much water the household uses, but far more often than a septic tank, in some cases monthly. A septic tank, by contrast, is usually pumped only every few years.
Can I use a holding tank instead of a septic tank?
Only where a drain field is not feasible or not allowed, such as poor soil, a high water table, or a lot with no room. Your local health department decides whether a holding tank is permitted for your site.
Do both need a permit?
Yes. Both septic and holding tank installations are regulated and require a permit and inspection from your local health department, which will also confirm the size and system your site needs.
Know which one you need? Find the right tank, or let our team help you match one to your site and local code.
