Before discussing Septic System Cost in Ontario, we first need to explain what is a septic system and why is it important.
Homes that aren’t connected to a municipal sewage system require an on-site septic system. The purpose of the septic system is to clean and purify human and household waste and return the filtered water back to nature.
In general, there are two main parts; a septic tank, and an absorption system, also called a drain field, leach field, or disposal field. These are located underground and connected to the house by sewage pipes.
To function well, the system must be designed to work with the number of bedrooms in the house, the size of the home, the layout of the site, and the composition of the soil that will handle the septic field.
The price of your septic is also highly dependent on the soil type. The drain field does not need to be as large for permeable soil conditions as it does for less porous soils.
Because of that, it is hard to accurately pinpoint the cost of any septic system. The only sure way to find out is to get some competing quotes. However, in the article below, we will give you valuable information that will help you figure out the costs.
So, What Is The Average Septic System Cost In Ontario?
There’s no way around it. Installing a new septic system is expensive. Sadly, there’s no generic answer to how much a septic system will cost. It will fluctuate in price depending on the following factors:
1. Soil Composition: It is much cheaper to build a septic system on sand than on the rock. Fine, silty soils require more drain field and are riskier to build due to slightly higher failure rates. Ultimately, the soil percolation test will need to be performed to determine the absorption rate of your soil.
2. The level of underground water: If you have a high water level on your lot, you will need to raise your septic field. That usually includes importing septic sand and installing a pump.
3. The size of the home and number of bedrooms: It should be self-explanatory that a septic system for a seven-bedroom mansion in the country will cost more than for the 1000 square feet cottage.
4. The type of septic system: There are many different types as there are costs. (More below).
5. Engineering costs: In some parts of southern Ontario, a qualified engineer and septic system contractor will be required to get the necessary health and sanitary permits, appropriate excavation at the site, and permission or approval from local building or planning officials. Some townships also require soil analysis.
6. The installer: Prices for the same job vary from installer to installer depending on their suppliers, job loads, etc.
7. The proximity of materials to your building site: Septic systems need a lot of materials to be trucked in. This includes a concrete tank, septic sand, clear stone, etc.
Ontario Building Code Regulates All Septic Systems in Ontario
All residential septic systems in Ontario must be built according to the Ontario Building Code, notwithstanding how the home will be used. The septic system is engineered the same, whether the residence is full-time or seasonal, or, whether only one person is occupying the house or four of them. The system must be built to meet the maximum use likelihood of the home, in the event, the property is sold, or changed from seasonal use to a year-round residence.
The guide below has been put together to assist you with understanding the minimum Ontario Building Code regulations for residential septic systems. You will be able to figure out what kind of septic system you need and approximate costs. Local governing health or building authorities may have additional by-laws in place requiring other design requirements.
First, let’s figure out what kind of system do you need:
All residential septic systems that are within a single lot and rated to accept a total daily flow rate of less than 10,000 L must abide by the Ontario Building Code. The two main items that dictate the size and design of a septic system in Ontario are the maximum daily flow rate and soil and site conditions.
How To Calculate Daily Flow Rate
All daily flow rate calculations start with the number of bedrooms. Most people believe it is based on the number of bathrooms or current occupants, but that is not the case.
The Ontario Building Code implies that for every bedroom, two people could be living in the home. The average daily use per person is 275 litres, and therefore, the maximum daily flow could be around 550 litres per bedroom.
Apart from the bedroom rate, you have to determine the number of fixtures, bathrooms, sinks, toilettes, etc.
If the total fixture count is greater than 20, then 50 litres per additional unit will need to be added to the bedroom rate.
The chart below will help you figure out the number of fixtures:
If your total is greater than 20, calculate the additional flow of 50 L for each added fixture. Round up for each half. For example, if your total is 22 1/2, then you may have to add 150 L to the base bedroom rate.
The Bedroom Rate:
The total living area will also need to be calculated to add additional litres per day to the base bedroom rate. The living area includes all living space, excluding the basement.
To the “bedroom rate,” you will need to add the higher of these numbers, as opposed to adding both together.
First, you will need to figure out if the living space is exceeding the included limit of 200 square meters (2152 sq.ft.). For every 10 square meters of living space over 200 square meters, you will need to add 100 litres to a max of 400 square meters. If your house is larger than 400 square meters, consult an engineer.
Once you have determined the living space and fixture count flow rates, whichever is greater is added to the base “bedroom rate.”
Let’s find the maximum daily flow rate for a four-bedroom home with three full bathrooms, extra sink in ensuite, kitchen sink, washer, laundry tub, dishwasher and total living space of 305 square meters (3282 square feet).
The base bedroom rate for four bedrooms is 2000 Liters. You have to figure out if you have to add to it.
Lets do the math: 3 full bathrooms = 18 + kitchen sink = 19.5 + extra sink = 21 + washer = 22.5 + laundry tub = 24 + dishwasher = 25.5.
So, for every fixture unit over 20, we have to add 50 litres.
Next, you need to figure out the combined flow rate due to living space over 200 square meters. There are an extra 104 square meters, and therefore, the added flow would be: 10.4 x 100 = 1,100 litres (rounded).
So, the largest of the living space – fixture count is 1,100 litres. That number has to be added to the 2000 litres bedroom rate so that the maximum daily flow (Q) will be 3100 litres.
The size of the septic tank is defined by this figure. The septic tank must be twice the daily flow, but no less than 3600 litres, except where a garburator is installed. In that case, the volume must be three times the daily flow. For the purpose of this example (without garburator), the size of the tank = 6200 litres or approximately 1400 imperial gallons.
How Site Conditions Determine The Size Of Septic Field
Now that we determined the daily flow rate, another detail we have to figure out is the rate at which the treated wastewater is absorbed into the ground. That is called a “T-time.” “T-time” is the number of minutes it takes for the water level to drop one centimetre in a test hole.
In sandy soils, “T-time” is usually less than 10. This means that it takes less than 10 minutes for the water level to drop 1 cm in the water-filled hole.
If you are dealing with clay soils, the “T-time” could be 50 or more as the small soil particles are slowing the rate of absorption.
Once the Daily Flow number and the “T-time” are identified, you can then figure out how large the septic field has to be.
Different systems have different equations to figure out the size of a septic bed.
As an example; Let’s take the most common drain field installed in Southern Ontario, a gravity-powered, conventional trench bed.
Total Trench Length would be decided by multiplying the daily flow rate by T time and multiplying by 200. (Q X T time) / 200.
For our house example, the total trench length would be calculated as (Q rate = 3100 litres) 3100 X 10 (T time for sandy soils) = 31000 / 200 = 155 meters of total excavation and pipe length.
If your “T-time” is = 50 or greater, regular runs can not be installed. A raised bed or “Advanced Treatment System” will need to be placed instead. A raised bed may require importing septic sand at the rate of $200 – $300 per truckload.
In general, gravity-powered sand filter beds (bottom right) are the least expensive. In most parts of Ontario, you can get such a system installed for $10,000 – $15,000.
The conventional gravity trench system (bottom left), for a three-bedroom house, on a level site, in good soil, can vary considerably depending on where you live, but it should be roughly between $10,000 to $20,000 depending on soil composition.
So, how much will your septic system cost?
To break it down, we will consider the costs and materials associated with the building of a traditional, single-family home, septic tank and a system using the gravity design.
A standard system will include:
Tank: It can be made of concrete, fibreglass or polyethylene and come in a variety of sizes. The most popular one is concrete, and these will cost around $1,300 to $2,500 depending upon size and installer.
Clear Stone: The amount of gravel required will vary by the soil type of the site and the overall landscape. The average cost of clean drain gravel at the time of this writing is between $30 and $50 per ton plus trucking time – approximately 2-3 truckloads.
Piping: This will vary according to the size and design of the system. Usually, around $20 per length for a 3″ perforated pipe.
Excavation equipment time: Usually, from $100 to $150 per hour.
Additional considerations and costs
If the area of your property receiving the leaching bed is hard to access and trees, rocks, or fencing must be removed, it will also add to the price.
You will also need to factor in the cost of sod or grass in the area after the septic installation is done.
The permitting costs: should not exceed $1,500 in fees for design and permit.
Like all larger home projects, the installation of a septic system should follow a pattern of soliciting several bids from qualified installers.
It is important to ask for references and proof of adequate liability insurance for a project such as this, and the work and materials should also have some guarantee or warranty as well.
Often an installer can even provide some maintenance agreement that will see the system pumped every one to three years and inspected annually.
Canadian Septic Discusses this subject here: https://www.canadianseptic.com/understanding-septic-system-pricing/
Pumping of your septic tank:
Remember, if you want a relatively trouble-free and long-lasting septic system, get your septic tank pumped on a regular basis.
How frequently you pump your septic system is determined mostly by the number of people living in the home. For an average-sized 2000 sq ft three bedrooms home the following timetable is suggested for pumping septic tanks: