Frequently Asked Questions About Building Regulations, Standards and Codes

1. What are the steps to building a septic system?
2. What is the process of approval under the OBC?
3. How does a small lot limit my on-site system?
4. How does a high water table affect the installation of an on-site system?
5. What is an Inappropriate soil and how does it limit my on-site system?
6. Are there any other limitations on my on-site system?
7. Why is there a loading rate for a raised bed?
8. Which is better to cover the stone in an absorption trench: untreated building paper or a geotextile fabric?
9. I was denied a septic permit. Can I appeal?
10. How can a sewage system inspector check the OBC’s requirements?
11. Does the OBC require that a "qualified supervisor" be on site?
12. What are the Installer responsibilities?
13. How can I locate my septic system?



Q1: What are the steps to building a septic system?

"I want to build a house in the country. Since there are no sewer lines in the area, I will need a septic system. What steps do I need to take to get the septic system built?"

Septic systems are permitted through your local building departments. A professional engineer is often required to conduct percolation tests and describe the soil below the area of the system. A good plot plan which shows distances from property lines, wells, and other site features should be drawn.

Septic systems must be at least 15 metres from all drilled wells and surface water. This distance increases to 30 metres for bored or dug wells. The size of the septic system is based upon the number of residents, the number of bedrooms, and from percolation test results. A licensed septic system installer must install the system.

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Q2: What is the process of approval under the OBC?

A permit is required for new construction; replacement of existing system; tank replacement; lines are added or lengthened. Generally the approval process is as follows:

  • pick up a permit, through local building/township office (you must pay at this time)
  • have soil sampled, and water table level established
  • eventually, soil is sent for testing
  • inspector visits the site to see the test pit and observe sub-surface conditions
  • hand in completed application form to local building/township office
  • inspector looks at application, soil report, reviews the proposed design
  • if acceptable, the permit is signed and given to the chief building official (can begin construction)
  • if not must re-work the design, work with inspector & designer
  • inspector will visit site again when the system is installed (not covered) to check separation distances, & general construction
  • inspector visits once more when system is fully done to give final approval

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Q3: How does a small lot limit my on-site system?

Some lots have an area that is too small to fit a conventional leaching bed. In cases such as these there may be alternative systems that require a smaller area which can be considered such as filter beds or shallow buried trench systems. The use of an advanced treatment unit can also reduce the foot print of the soil absoprtion system by up to one third.

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Q4: How does a high water table affect the installation of an on-site system?

All absorption trench systems must meet a minimum vertical separation distance to the seasonally high water table of 900 mm from the bottom of the trench. In areas where the water table does not permit the installation of conventional inground absorption trenches, a raised system can be installed. This can be a raised conventional system, or a raised filter bed system. Alternatively, an advanced treatment unit with an area bed could also be installed as some area beds have reduced vertical separation distances.

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Q5: What is an Inappropriate soil and how does it limit my on-site system?

An inappropriate soil for a conventional inground on-site system is one where thepercolation time (T-time) is greater than 50 min/cm or less than 1 min/cm. (OBC Section 8.7.2.1) In this case a raised bed must be installed. Alternatively, a shallow buried trench system may be installed in native soils with a T-time from 1 min to 125 min.

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Q6: Are there any other limitations on my on-site system?

There are a number of limitations on the use of an on-site system including:

  • cannot pave over the leaching bed
  • should not plant trees in the leaching bed
  • cannot drive heavy equipment over the leaching bed
  • must meet all minimum distance requirements: to well; to property line; to house/structure; to river, lake or stream or spring as defined in the Ontario Building Code
  • septic tank must be accessible

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Q7: Why is there a loading rate for a raised bed?

The OBC require that the mantle area for a raised bed or a filter bed be designed for a specified loading rate. The OBC sets a loading rate to prevent effluent break out from the sides of the leaching bed or mantle area where difficult soil conditions exist. It has been the experience of enforcement agencies that the construction of raised beds and filter beds under such conditions may require that the mantle area be extended for more than the 15 metre minimum.

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Q8: Which is better to cover the stone in an absorption trench: untreated building paper or a geotextile fabric?

Section 8.7.3.3.(2) of OBC requires that the stone covering the distribution pipe be covered with untreated building paper or a permeable geotextile fabric.

The purpose of this separator is to prevent soil or leaching bed fill from entering the stone during backfill. Although both are allowed, the untreated building paper will decompose within a few months compared to a geotextile which will last the life of the tile bed.

Q9: I was denied a septic permit. Can I appeal?

Yes. If there is a dispute between an applicant for or holder of a building permit or a person to whom an order under the Building Code Act has been given and a sewage system inspector, either party can apply to the Building Code Commission (BCC) for a resolution of the dispute. The BCC deals with matters related to the interpretation of the technical standards in the OBC or the sufficiency of compliance with these technical standards

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Q10: How can a sewage system inspector check the OBC’s requirements?

The OBC requires that septic tanks conform with the requirements of CSA Standard CAN3- B66 — Prefabrication Septic Tanks and Sanitary Sewage Holding Tanks. This standard requires that certain information be marked on the tank. In addition, building officials can request that certain tests be completed or documents provided to satisfy themselves that tanks conform with the OBC requirement and CSA standard.

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Q11: Does the OBC require that a "qualified supervisor" be on site?
The qualified supervisor shall be on site to provide direction to other staff at critical points in the installation and to meet with the inspector to ensure that the project is progressing as planned. As with any other type of construction project, he/she does not have to be on site throughout the project.

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Q12: What are the Installer responsibilities?

"I am a licensed septic installer starting to construct a septic system. After starting site preparations I realize the plans that were provided will not work on this lot. What are my responsibilities?"

It is the Installer’s responsibility to make sure that the constructed on-site system meets the requirements of the OBC and conforms with the permit issued for the system. The Installer must contact the designer and the regulator before making any changes or alterations to the approved plans and specifications. The Regulator must approve any change made to the design after a permit has been issued and before implementing the changes.

Further information on septic installations can be obtained from Building Code Interpretation Services by visiting the Housing Development and Buildings Branch’s homepage.

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Q13: How can I find the location of my septic system?

County health departments issue permits and inspect systems as they are installed. If your system has been installed in the last 20 years they may have a sketch of the layout of the system.

Septic system pumpers can usually find the tank by using a soil probe in areas where they would expect to find a tank. Tanks are usually behind the house, near the bathroom, and about 10 feet away from the foundation.

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