In our daily lives we shower, wash dishes and clothes and go to the bathroom. We use sinks and toilets and what we put in them gets flushed down the drain and few of us ever consider where that goes. Most people, especially those who live in large metropolitan areas, are familiar with the concept of a sewer but don’t really understand what that involves. A Sewer is basically a network of pipes that collect all the used water and waste from every house and building, what we will call the waste stream, and conveys this to a central facility. All the water that came into our homes and buildings, through your facets for example, originally came from our environment and eventually, goes back out into that environment. It is reasonable to assume that no one wants to see what we flushed down the drain end up in our environment, rather we would like to see clean clear fresh water. So that central facility must treat the waste stream. It does this by removing the solids, neutralizing the chemicals, bacteria and viruses as much as possible and purifying the water. This purified water then gets put back into the environment.
So, what do you do if you can’t connect to the sewer system, say when you live in a remote or rural area?
You install your own sewage treatment facility in miniature, designed to do the exact same thing but only large enough for your house, and all the water that comes into your house goes back out into your land. For these facilities the land is also an active part of the treatment process.
In the past we called these “septic systems”, and many folks still do, but that is the name of an older style of system, what we call a Type 1 System. Because available lots are not as large or as flat as they used to be it is not nearly as common to use them anymore. Nowadays, we refer to the systems as Onsite Wastewater Systems, OWS or wastewater systems. This terminology encompasses all the broad range of system options we have available.
What is the first step in preparing for an Onsite Wastewater System?
The first step in preparing for a wastewater system is to consult a qualified person who specializes in waste water treatment system planning and/or installation. Not only will they tell you what is likely to be the best solution for you, but they can also tell you how much you need to budget. If you are using an architect then you should ensure the architect and the engineer can work together, the results may amaze you.
In BC, in areas serviced by onsite wastewater systems, you can only get a building permit after you have filed a Record of Sewerage System or RSS and a Sewerage System Plan with the local Regional Health Authority; a copy of this document and a “Receipt of Record of Sewerage System” letter is what you (or your agent/engineer) files with the building permit office. This is proof that a plan has been filed.
The Record of Sewerage System requires a detailed plan of what is to be installed for a wastewater system. This includes site data and flow calculations as well as a site plan and details of the installed system and components. Remember too that the site assessment, and subsequent design for that matter, must also address the needs of surrounding properties to ensure they are not negatively affected by what you plan to do.
The qualified person we spoke of may be either a practitioner, as registered with ASTTBC or an engineer licensed to practice in BC. If a person you have chosen has neither of these designations or has not filed a plan, then the installation is not allowed under the Health Act. However, unregistered persons, including homeowners, may install systems if supervised by an engineer [but not by a registered practitioner]. All engineers and registered practitioners must carry errors and omissions insurance to cover the work they do.
Whether you choose an engineer, or a registered practitioner depends on the complexity of your site and plans. When sites are complex, flow volumes are above certain mandated levels or advanced treatment plants are being considered then you should consult an engineer.
Designing and filing typically may take from 2 weeks to a month. A site assessment is always required, and the data gathered is used along with survey information and your building plans to create the plan that is filed. A simple site installation can take as little as a couple of days if everything is on site already however if it is a new building site then typically this may occur in stages over a longer period as other construction work on the site proceeds.
How much does it cost?
First, keep in mind that equipment and material costs have gone up a lot in the last few years due in part to the cost of energy and shipping. Second, the current sewerage systems regulation is much more stringent than the previous regulation, so more materials are required. There is a prevalent misconception that wastewater systems are supposed to be inexpensive – they are not and never were when correctly installed. However, a properly designed system can be very reasonably priced keeping in mind that the bigger the house you build the bigger the wastewater system will have to be. A typical Type 1 system (anaerobic treatment only) will be between $9000 and $11000. A typical Type 2 aerobic treatment system will be between $12000 and $17000. A typical Type 3 advanced treatment system will be between $18,000 and $35,000+. This may seem steep but considering that you should get at least 30 years of reliable service [out of site out of mind] from such a system then its certainly much better value for your money than a car. Where a system has been properly maintained the lifetime of the system (with maybe a pump replacement) should be indefinite.
Any time the site is more challenging and requires more machine work the cost will increase; very small sites also are more difficult to work with and the system will cost more.
In comparing treatment levels Type 3 systems are always more expensive because they are designed for much more demanding applications, although there are exceptions. Any time you must pump to a disposal location you will also incur more cost.
Remember, you need space for the system, the lower the treatment level the greater the amount of space required.
It is also important to consider the location and requirements of the wastewater treatment system when you are siting your new house. Sometimes, moving your house upslope a few tens of meters can result in a better solution with lower cost; it might even provide a better view!
Compiled by: Bert Telder, P. Eng. –
Bert Telder, P. Eng.
Telder Engineering Ltd.