Ken White Construction Logo

Septic System Don’ts

Educational Resources

Septic System Don’ts

Here is a list of things Ken White Construction suggests you avoid as an on-site septic system owner. Some of the suggestions pertain to products, some to design & others to property care. We hope that you find this list helpful & as always, let us know if you have any questions. Comment, start a new chat or visit our Ken White Construction Facebook page.

Household Products

Do not flush female sanitary products, cotton balls, swabs or condoms. These items will clog the system & eventually lead to back up. Antimicrobial soaps & automatic disinfection tablets (clear, blue or otherwise) may kill the organisms needed to consume waste. 

Commercial Additives

There is no evidence to support the use of additives with normally functioning septic systems. Some septic tank additives have even been shown to do more harm than good. A normally functioning system should not require additives as it has all of the natural bacteria & enzymes to digest the wastewater that enters the system.

Chemicals & Toxins

These materials kill the microbes necessary for the biological treatment to occur. Don’t dump or drain these materials into your water supply & ultimately your septic system. Paint, paint thinner, solvents, volatile substances, drain cleaners, automotive fluids, fuels, pesticides, herbicides, fertilizers, metals, disinfectants, sanitizers, bleach, mop water, floor stripping wastes, excessive use of household chemicals & backwash from water softener regeneration. 

Laundry Practices

On-site systems must process the water as it enters the system. Laundry should be spread out over the week, not all run at once. This reduces the stress on your septic system. Excessive use of detergents, especially those containing bleach, can affect system performance. Liquid detergents are recommended over powders. Fabric softener sheets are recommended over liquid softeners. Bleach should be used sparingly & at half the rate indicated on the container. 

Clear Water Waste

From A/C discharge lines, floor drains, gutters, whole house water treatment systems & sump pumps can increase the flow to your treatment system. These flows can at least disrupt, if not destroy your treatment process by overloading the system. 

Design Capacity 

Do not overload the system beyond design capacity. A septic system is designed to handle a certain amount of sewage daily. Any use above the design flow will decrease the holding time in the tank. This will result in untreated solids entering the leaching bed. In time, this results in the pores of the leaching field becoming clogged. Untreated sewage will also carry pathogenic bacteria, viruses & pollutants in unacceptable amounts. 

Trees & Shrubs

Do not plant trees or shrubs close to the septic bed. Tree & shrub roots travel significant distances in search of water, especially willows & poplars. Planting trees & shrubs close to or in the septic field will result in the roots growing into the perforated pipes of the septic field. This causes blockage & damage. A minimum distance of 6.0 metres should be kept between trees & the outer pipes of the leaching field. 

Drainage Patterns

Do not change the drainage pattern of the septic bed landscape. All runoff has to be directed away from the septic bed. Swales are used to direct rainwater & melting snow away from the leaching bed. Filling them will change the pattern. 


Do not install automatic sprinklers over the septic bed. You do not want to overload the sand area of your septic system with extra water.

Inert Materials

Plastic, rubber, scouring pads, dental floss, kitty litter, cigarette filters, bandages, hair, mop strings, lint, rags, cloth & towels do not degrade in an on-site treatment system. Inert materials will build up solids & lead to system malfunction, clogging or increased pump out frequency.

Paper Products

Disposable diapers, paper towels, baby wipes, facial tissues, toilet tissue that is lotioned, scented or quilted & moist towelettes do not dissolve readily in an onsite treatment system. Excessive amounts of toilet tissue will also not decompose. All can lead to system malfunction, back-up or increased pump out frequency. 

Food Wastes

Do not put animal fats & bones, grease, coffee grounds, citrus & melon rinds, corn cobs or egg shells down the sink. Garbage disposal use should be limited to waste that cannot be scooped out & thrown out. Spoiled dairy products & yeasts from home brewery or baking may cause excessive growth of microbes that do not degrade the sewage. 

Medications & Ailments

Normal use of over the counter medications do not affect the performance of onsite systems. However, do not flush expired medicines or antibiotics into an onsite treatment system. Some prescription medications are known to cause biological disrupt which may cause issues in your treatment system. Other instances where biological disrupt needs to be taken into account are sufferers of bulimia, severe infections (including AIDS), chronic diarrhea, intestinal/colon by-pass, other gastrointestinal conditions & cancer. Oral & intravenous chemotherapy are known to cause severe disruption to the treatment process & require more frequent pump out intervals or the use of biologically based additives. 

System Location

Do not dig without knowing the location of your septic tank & leaching bed area. Digging near your septic system components can result in damage to the tank & leaching bed, which could result in an expensive repair bill. 


Do not drive over the septic system or use it as a parking/storage area. Driving cars or machinery over your septic system will result in crushing the pipes & compacting the soil. This reduces the water absorbing capacity of your system. Even snowmobiles compress the snow cover of the field which will reduce the insulating effect of the snow & could lead to the pipes freezing. 


Do not connect rain gutters or sump pumps to the septic system. Septic beds are not designed to handle this additional flow.

Do not direct furnace condensate & water softener backwash to the septic system. Direct them to leaching pits away from the septic system. 


Do not change the structure of the house without consulting your septic system designer & the appropriate approval agency. Adding an apartment in the basement, plumbing fixtures, or any changes to usage may result in additional flow that could be detrimental to your septic system. The building code requires that any changes to your domicile be approved prior to work commencement. 

Do not build any structure over your septic system. For example, patios, tennis courts, swimming pools, driveways, retaining walls & skating rinks cannot be built over any part of your septic system.

Share on Facebook
Share on Twitter

Subscribe To Our Socials

Check out our YouTube & other socials for more great construction content!

KWC Resources

Like This? Check Out More Of Our Resources

A family run business with over 50 years experience, we are proud of our ability to bring these learning resources to you. Learn more from our hard working and professional team today.