Having a beautiful patio in your property can be one of the most enjoyable and rewarding additions to your home. No matter what’s its size is or how you decorate it, a finished patio is a place for you to relax, have fun and enjoy nature over a cup of tea. And therefore, there is nothing wrong to want to build an alluring patio on your outdoors too.
However, after you zero in the most beautiful place in your yard to build your dream patio, if you find out there is a septic tank in the way, how would you feel?
It’s not an uncommon scenario in America. As, according to a 2007 survey conducted by NSCEP, an estimated 20% [26.1 million]of the total US houses have a septic system, it is more likely that you would find one on your property too. And when you do, the first question that hits your mind is “can you build a patio over a septic tank or not.
Even though it’s not impossible, you must never build a patio over a septic tank. It might not only be against the planning laws of your state or locality but it is dangerous too. As septic tanks are not built to stand the weight of a concrete or pavers patio, building them over it will cause serious damage to the tank and the waste lines and expose you to severe safety hazards.
5 Risks of Building a Patio Over a Septic Tank
Putting a patio over a septic tank is a risky business. Let’s discuss what can you put over a septic tank and these risk factors in detail for better understanding.
- As a septic tank is a place for the all the wastage of your home, it imposes health hazards on the human body. The harmful sewer gases and toxins, especially carbon monoxide, can be extremely dangerous for humans can cause a number of health problems including Shigellosis, Diarrhea, and trachoma.
In some fatal cases, septic tank gas poisoning can cause death too. If you build a patio on it, you would expose yourself, as well as your guests, to these hazardous gas and toxins and make you sick over the period. - Besides being fatal for your health, the septic tank gases and toxins are also dangerous for the patio floor too. The continuous buildup of hydrogen sulfide eats the concrete surface of the tank lid over time and might make it collapse causing dreadful accidents.
- Building a patio on a septic tank can be hazardous for the tank too. As these tanks are not built to withstand the weight, building a patio over them, especially concrete or pavers patio, will cause serious damage to not only the tank but the waste lines also.
- A septic tank requires regular maintenance. You need to pump and empty it every three to five years to keep the drainage system running smoothly. If you build a patio over it, the structure will make it extremely difficult to pump the tank as regularly as it needs and affect your house drainage and waste management system greatly.
- Additionally, a patio on or near the septic tank might damage the waste lines as well as the drain field too. The heavy structure, even on the edge of the tank will damage the pipes and drain field and make the effluent [liquid waste] flow in the ground. It will release a foul smell and make the surroundings unappealing.
You may read also: How To Keep Your Patio Healthy For Fun
How Much Weight Can Go on a Septic Tank?
There is no exact weight limit that a septic tank can endure. This is because it depends on other factors like the soil, construction as well as how old the tank is. However, keeping all these factors in consideration, well-built septic can withstand 500–700 gallons of weight before it falls apart.
How close can I build my patio to a septic tank?
If you have a septic tank in your outdoors and you are planning to build a patio, make sure that you build it at least 5-6 feet away from the edge of the tank so that you don’t disturb the septic system.
Can you put a concrete slab over a septic tank?
Just like any other heavyweight thing, you shouldn’t ever put a concrete slab over your septic tank. EVER! As a concrete slab is extremely heavy in weight, it will damage the septic system and might even cause wastage to flow out.
Can you build a patio over an old, unused septic tank?
You must never patio over an old, abandoned septic tank. It is strongly discouraging. Even if it is no longer in use and you have pumped out all the liquid from it, it is still extremely dangerous. Because the tank is sealed, it has methane gas and other toxins buildup, which over time might burst and make the patio collapse.
If it’s extremely necessary to use this part of the land, remove the tank first to ensure your safety.
Can I build a deck over a septic tank instead of a patio?
You should avoid building a deck on a septic tank for the same reasons you cannot construct a patio over it. It doesn’t matter if it’s a deck or a patio, a septic tank isn’t the ideal place to build anything over it.
Final Thoughts
A patio is an incredible addition to your yard. Hope you have already gotten an idea about Can You Build A Patio Over A Septic Tank. However, it’s just not the right structure to build over a septic tank. As it is extremely dangerous and also has health hazards, it would be a wise decision to build the structure anywhere in the yard except on or near the tank.

Henry Jurk is an experienced architect with over 20 years of expertise in paving. He shares his knowledge and provides solutions through his blog posts at OkPatio.com. If you have any questions about patios, gardens, and outdoor spaces, you can find the correct answers from Henry. You can contact him via email at ar.henryjurk@gmail.com or through the website’s contact page.