A Homeowner’s Guide to Septic Systems

Your septic system is your responsibility

Did you know that as a homeowner, you’re responsible for maintaining your septic system? Did you know that maintaining your septic system protects your investment in your home? Did you know you should periodically inspect your system and pump out your septic tank?

If properly designed, constructed and maintained, your septic system can provide long-term, effective treatment of household wastewater. If your septic system isn’t maintained, you might need to replace it, costing you thousands of dollars. A malfunctioning system can contaminate groundwater, which might be a source of drinking water. And if you sell your home, your septic system must be in good working order.

This guide will help you care for your septic system. It will help you understand how your system works and what steps you can take as a homeowner to ensure your system will work properly.

Top four things you can do to protect your septic system

  1. Regularly inspect your system and pump your tank as necessary.
  2. Use water efficiently.
  3. Don’t dispose of household hazardous wastes in sinks or toilets.
  4. Care for your drain field.

How does a septic system work?


A typical septic system has four main components: a pipe from the home, a septic tank, a drain field and the soil. Microbes in the soil digest or remove most contaminants from wastewater before it eventually reaches groundwater.

Image of a Typical onsite wastewater treatment system

Typical onsite wastewater treatment system

Pipe from the home

All of your household wastewater exits your home through a pipe to the septic tank.

Septic tank

The septic tank is a buried, watertight container typically made of concrete, fibreglass, or polyethylene. It holds the wastewater long enough to allow solids to settle out (forming sludge) and oil and grease to float to the surface (as scum). It also allows partial decomposition of the solid materials. Compartments and a T-shaped outlet in the septic tank prevent the sludge and scum from leaving the tank and travelling into the drainfield area. Screens are also recommended to keep solids from entering the drainfield.

Newer tanks generally have risers with lids at the ground surface to allow easy location, inspection, and tank pumping.

Septic system aliases:
  • On-lot system
  • Onsite system
  • Individual sewage disposal system
  • Onsite sewage disposal system
  • Onsite wastewater treatment system
Image of Typical single-compartment septic tank with ground-level inspection risers and screen

Typical single-compartment septic tank with ground-level inspection risers and screen

Tip: To prevent buildup, sludge and floating scum need to be removed through periodic pumping of the septic tank. Regular inspections and pumping are the best and cheapest way to keep your septic system in good working order.

Finding Your System

Your septic tank, drainfield, and reserve drainfield should be clearly designated on the “as-built” drawing for your home. (An “as-built” drawing is a line drawing that accurately portrays the buildings on your property and is usually filed in your local land records.) You might also see lids or manhole covers for your septic tank. Older tanks are often hard to find because there are no visible parts. An inspector/pumper can help you locate your septic system if your septic tank has no risers.

Image of Septic tank, drain field, soil, and groundwater


The wastewater exits the septic tank and is discharged into the drain field for further treatment by the soil. The partially treated wastewater is pushed along into the drainfield for further treatment every time new wastewater enters the tank.

If the drainfield is overloaded with too much liquid, it will flood, causing sewage to flow to the ground surface or create backups in plumbing fixtures and preventing treatment of all wastewater.

A reserve drain field may be required by some jurisdictions; this is an area on your property suitable for a new drain field system if your current drain field fails. Treat this area with the same care as your septic system.


Septic tank wastewater flows to the drain field, where it percolates into the soil, which provides final treatment by removing harmful bacteria, viruses, and nutrients. Suitable soil is necessary for successful wastewater treatment.

Alternative systems

You might have or need an alternative system because many areas don’t have soils suitable for typical septic systems. You might also have or need an alternative system if there are too many typical septic systems in one area or the systems are too close to groundwater or surface waters. Alternative septic systems use new technology to improve treatment processes and might need special care and maintenance. Some alternative systems use sand, peat, or plastic media to promote wastewater treatment instead of soil. Other systems might use wetlands, lagoons, aerators, or disinfection devices. Alternative systems often use float switches, pumps, and other electrical or mechanical components. Alternative systems should be inspected annually. Check with your local health department or installer for more information on operation and maintenance needs if you have or need an alternative system.

Why should I maintain my septic system?

When septic systems are properly designed, constructed, and maintained, they effectively reduce or eliminate most human health or environmental threats posed by pollutants in household wastewater. However, they require regular maintenance, or they can fail. Septic systems must be monitored to ensure they work properly throughout their service lives.

Saving money

A key reason to maintain your septic system is to save money! Failing septic systems are expensive to repair or replace, and poor maintenance is often the culprit. Regularly inspecting your septic system is a bargain when considering the cost of replacing the entire system. Your system will need pumping depending on how many people live in the house and the size of the system. An unusable septic system or one in disrepair will lower your property value and could pose a legal liability.

Protecting health and the environment

Other good reasons for safe sewage treatment include preventing infection and disease and protecting water resources. Typical pollutants in household wastewater are nitrogen, phosphorus, and disease-causing bacteria and viruses. If a septic system works properly, it will remove most of these pollutants effectively.

With 15% of Canadian homes using septic systems, more than 1 billion litres of wastewater daily is dispersed below the ground’s surface. Inadequately treated sewage from septic systems can be a cause of groundwater contamination. It poses a significant threat to drinking water and human health because it can contaminate water wells and cause diseases and infections in people and animals. Improperly treated sewage contaminating nearby surface waters also increases the chance of swimmers contracting various infectious diseases, ranging from eye and ear infections to acute gastrointestinal illnesses and diseases like hepatitis.

How do I maintain my septic system?

Inspect your tank

You should have a typical septic system inspected at least every three years by a professional and your tank pumped as the inspector recommends (generally every 3 to 5 years). Alternative systems with electrical float switches, pumps, or mechanical components must be inspected more often, generally once a year. Your service provider should inspect for leaks and look at the scum and sludge layers in your septic tank. If the bottom of the scum layer is within 6 inches of the bottom of the outlet tee or the top of the sludge layer is within 12 inches of the outlet tee, your tank needs to be pumped. Remember to note the sludge and scum levels determined by your service provider in your operation and maintenance records. This information will help you decide how often pumping is necessary.

Pump regularly

Four major factors influence the frequency of pumping: the number of people in your household, the amount of wastewater generated (based on the number of people in the household and the amount of water used), the volume of solids in the wastewater (for example, using a garbage disposal increases the amount of solids), and septic tank size.

Some makers of septic tank additives claim that their products break down the sludge in septic tanks so the tanks never need to be pumped. Not everyone agrees on the effectiveness of additives. In fact, septic tanks already contain the microbes they need for effective treatment. Periodic pumping is a much better way to ensure that septic systems work properly and provide many years of service. Regardless, every septic tank requires periodic pumping.

In the service report, the pumper should note any repairs completed and whether the tank is in good condition. If the pumper recommends additional repairs he or she can’t perform, hire someone to make the repairs as soon as possible.

Care for your drain field

Your drain field is an important part of your septic system. Here are a few things you should do to maintain it:

  • Plant only grass over and near your septic system. Roots from nearby trees or shrubs might clog and damage the drain field.
  • Don’t drive or park vehicles on any part of your septic system. Doing so can compact the soil in your drain field or damage the pipes, tank, or other septic system components.
  • Keep roof drains, basement sump pump drains, and other rainwater or surface water drainage systems away from the drain field. Flooding the drain field with excessive water slows down or stops treatment processes and can cause plumbing fixtures to back up.

Conserve water

The average indoor water use in the typical single-family home is over 300 litres per person daily. Leaky toilets can waste as much as 200 gallons each day. The more water a household conserves, the less water enters the septic system. Efficient water use can improve the operation of the septic system and reduce the risk of failure.

  • Install high-efficiency showerheads
  • Fill the bathtub with only as much water as you need
  • Turn off faucets while shaving or brushing your teeth
  • Run the dishwasher and washing machine only when they’re full
  • Use toilets to flush sanitary waste only (not kitty litter, diapers, or other trash)
  • Make sure all faucets are completely turned off when not in use
  • Maintain your plumbing to eliminate leaks
  • Install aerators in the faucets in your kitchen and bathroom
  • Replace old dishwashers, toilets, and clothes washers with new, high-efficiency models

For more information on water conservation, visit Alberta WaterPortal | Tips for conserving water

High-efficiency toilets

Toilet use accounts for 25 to 30 percent of household water use. Do you know how many gallons of water your toilet uses to empty the bowl? Most older homes have toilets with 3.5- to 5-gallon reservoirs, while newer high-efficiency toilets use 1.6 gallons of water or less per flush. If you have problems with your septic system being flooded with household water, consider reducing the volume of water in the toilet tank if you don’t have a high-efficiency model or replacing your existing toilets with high-efficiency models.

Faucet aerators and high-efficiency showerheads

Faucet aerators help reduce water use and the volume of water entering your septic system. High-efficiency showerheads or shower flow restrictors also reduce water use.

Water fixtures

Ensure your toilet’s reservoir isn’t leaking into the bowl. Add five drops of liquid food colouring to the reservoir before bed. If the dye is in the bowl the next morning, the reservoir leaks and repairs are needed.

A small drip from a faucet adds many gallons of unnecessary water to your system every day. To see how much a leak adds to your water usage, place a cup under the drip for 10 minutes. Multiply the amount of water in the cup by 144 (the number of minutes in 24 hours, divided by 10). This is the total amount of clean water travelling to your septic system each day from that little leak.

Watch your drains

What goes down the drain can have a major impact on how well your septic system works. What shouldn’t you flush down your toilet? Dental floss, feminine hygiene products, condoms, diapers, cotton swabs, cigarette butts, coffee grounds, cat litter, paper towels, and other kitchen and bathroom items can clog and potentially damage septic system components if they become trapped. Flushing household chemicals, gasoline, oil, pesticides, antifreeze, and paint can stress or destroy the biological treatment taking place in the system or might contaminate surface waters and groundwater. If your septic tank pumper is concerned about quickly accumulating scum layers, reduce the flow of floatable materials like fats, oils, and grease into your tank or be prepared to pay for more frequent inspections and pumping.

Washing machines

By selecting the proper load size, you’ll reduce water waste. Washing small loads of laundry on the large-load cycle wastes precious water and energy. If you can’t select load size, run only full loads of laundry.

Doing all the household laundry in one day might seem like a time-saver, but it could harm your septic system. Doing load after load does not allow your septic tank time to adequately treat wastes. You could be flooding your drain field without allowing sufficient recovery time. Try to spread water usage throughout the week. A new Energy Star clothes washer uses 35 percent less energy and 50 percent less water than a standard model.

What can make my system fail?

If the amount of wastewater entering the system is more than the system can handle, the wastewater backs up into the house or yard, creating a health hazard.

You can suspect a system failure not only when a foul odour is emitted but also when partially treated wastewater flows up to the ground surface. However, the damage might already be done when you can smell or see a problem.

Limiting your water use can reduce the amount of wastewater your system must treat. When your system is inspected and pumped as needed, you lessen the chance of system failure.

A system installed in unsuitable soils can also fail. Other failure risks include inaccessible tanks for maintenance, drain fields that are paved or parked on, and tree roots or defective components that interfere with the treatment process.

Failure symptoms

The most obvious septic system failures are easy to spot. Check for pooling water or muddy soil around your septic system or basement. Notice whether your toilet or sink backs up when you flush or do laundry. You might also notice strips of bright green grass over the drainfield. Septic systems also fail when partially treated wastewater comes into contact with groundwater. This type of failure is not easy to detect, but it can result in the pollution of wells, nearby streams, or other bodies of water. Check with a septic system professional and the local health department if you suspect such a failure.

Failure causes 

Household toxics 

Does someone in your house use the utility sink to clean out paint rollers or flush toxic cleaners? Oil-based paints, solvents, and large volumes of toxic cleaners should not enter your septic system. Even latex paint cleanup waste should be minimized. Squeeze all excess paint and stain from brushes and rollers on several layers of newspaper before rinsing. Leftover paints and wood stains should be taken to your local household hazardous waste collection center. Remember that your septic system contains living organisms that digest and treat waste.

Household cleaners

For the most part, your septic system’s bacteria should recover quickly after small amounts of household cleaning products have entered the system. Of course, some cleaning products are less toxic to your system than others. Labels can help key you into the potential toxicity of various products. The label “Danger” or “Poison” indicates that the product is highly hazardous. “Warning” tells you the product is moderately hazardous. “Caution” means the product is slightly hazardous. (“Nontoxic” and “Septic Safe” are terms created by advertisers to sell products.) Regardless of the product type, use it only in the amounts shown on the label instructions and minimize the amount discharged into your septic system.

Hot tubs and swimming pools

Hot tubs are a great way to relax. Unfortunately, your septic system was not designed to handle large quantities of water from your hot tub. Emptying hot tub water into your septic system stirs the solids in the tank and pushes them out into the drainfield, causing it to clog and fail. Draining your hot tub into a septic system or over the drain field can overload the system. Instead, drain cooled hot tub water onto turf or landscaped areas well away from the septic tank and drain field and follow local regulations. Use the same caution when draining your swimming pool.

Water purification systems

Some freshwater purification systems, including water softeners, unnecessarily pump water into the septic system. This can contribute hundreds of gallons of water to the septic tank, causing agitation of solids and excess flow to the drain field. Check with your licensed plumbing professional about alternative routing for such freshwater treatment systems.

Garbage disposals

Eliminating the use of a garbage disposal can reduce the amount of grease and solids entering the septic tank and possibly clogging the drainfield. A garbage disposal grinds kitchen scraps, suspends them in water, and sends the mixture to the septic tank. Once in the septic tank, some materials are broken down by bacterial action, but most grindings must be pumped out. Using a garbage disposal frequently can significantly increase the accumulation of sludge and scum in your septic tank, resulting in the need for more frequent pumping.

Improper design or installation

Some soils provide excellent wastewater treatment; others don’t. For this reason, the design of the drain field of a septic system is based on the soil analysis results. Homeowners and system designers sometimes underestimate the significance of good soils or believe soils can handle any volume of wastewater applied to them. Many failures can be attributed to having an undersized drain field or a high seasonal groundwater table. Undersized septic tanks — another design failure — allow solids to clog the drain field and result in system failure.

If a septic tank isn’t watertight, water can leak into and out of the system. Usually, water from the environment leaking into the system causes hydraulic overloading, taxing the system beyond its capabilities and causing inadequate treatment. Sometimes, sewage flows up to the ground surface. Water leaking out of the septic tank is a significant health hazard because the leaking wastewater has not yet been treated.

Even when systems are correctly designed, failures due to poor installation practices can occur. If the drain field is not levelled correctly, wastewater can overload the system. Heavy equipment can damage the drainfield during installation, leading to soil compaction and reducing the wastewater infiltration rate. And if surface drainage isn’t diverted from the field, it can flow into and saturate the drainfield.

Septic System Dos and Don’ts


  • Do conserve water. Putting too much water into the system can eventually lead to system failure.
  • Do repair leaky faucets or toilets and install high-efficiency fixtures.
  • Do avoid long showers.
  • Do clean the toilets, sinks, showers, and tubs with a mild detergent or baking soda instead of commercial-grade cleaners and laundry detergents.
  • Do keep records of repairs, pumpings, inspections, permits issued, and other system maintenance activities.
  • Do keep a sketch of your system including measurements from two points on the house.
  • Do have your septic system inspected and pumped as part of a regular home maintenance plan.
  • Do have only grass over your septic system. Roots from nearby trees or shrubs could cause problems for the absorption area.


  • Don’t use your septic system like a trash can. Don’t put dental floss, feminine hygiene products, condoms, diapers, cotton swabs, cigarette butts, coffee grounds, cat litter, paper towels, latex paint, pesticides, or other hazardous chemicals into your system.
  • Don’t use commercial-grade drain cleaners to clear a clogged drain. Instead, use boiling water or a drain snake to open clogs.
  • Don’t allow surface water to flow over the tank or absorption area.
  • Don’t drive heavy equipment, trucks or vehicles over any part of your septic system. Doing so can compact the soil in your drain field or damage the pipes, tank, or other septic system components.
  • Don’t dig in the absorption area.

Septics 101: A Guide to Septic System Maintenance