A diary of the projects, hurdles, rewards and family life at we recorded at Wise Acres, our former homestead in Horsefly, BC. (Careers and teenagers have forced us back into the city, at least for a little while.)

Friday, April 4, 2008

A Septic's (sic) Guide to Wastewater Management in BC

(Image via Flickr courtesy of cobalt123. Considering the topic, why not show something pretty and nice-smelling?)

Last week I wrote about our well. Well this week, I felt it would be appropriate to write about the dirtier end of the dousing rod - the septic system.

One of the subjects on our purchase of the property was to check the condition of the septic system. I have no prior experience with anything remotely resembling this, so I googled away, hoping to find some information to help me unmuddy these waters before I waded into this (hopefully forever figurative) morass. I found nothing. Even without "BC" as a search condition, there isn't much published out there.

However, once I had a specialist or two involved, my confusion began to flush away. They introduced me to the rules in simple terms, and eventually I learned about the BCOSSA web site.

Some background...
The system on this property is a lagoon, supposedly low-maintenance and inexpensive. The waste matter is sent to the bottom of the lagoon by gravity (and your house should be higher than the top of the berm - you can figure that one out!), then naturally treated anaerobically in the depths of the pool, and as the 'fresh' water rises to the top, it eventually evaporates. There is almost no seepage into the ground, unlike leeching fields. Ideally, every member of the family should be accommodated by about 500 sq.ft. of lagoon surface. The regulations for those in BC are pretty straightforward:

Sites are considered to be suitable for a Lagoon system when they have, in addition to the standards outlined in Table 2-6 and Table 2-7:
  • a minimum area of 4.0 acres;
  • soils with a soil percolation rate equal to or slower than 60 minutes/2.5 cm (1 inch) or Kfs less than 20 mm/day and no rock within 1 m vertical depth from the bottom of the lagoon;
  • a minimum unsaturated vertical depth from the bottom of the lagoon of 0.91 m(36");
  • a soil percolation rate equal to or slower than 60 minutes/2.5 cm (1 inch) or Kfs less than 15 mm/day at the lagoon base, below the lagoon berms and in the completed berms; and,
  • a slope no greater than 12% (except where berms are designed by a Professional).
(excerpt from section LAGOON SYSTEMS,
of the SEWERAGE SYSTEM Standard Practice Manual Version 2)

Lagoons should be oriented along the surface contours in order to reduce slope variation. When laying out a lagoon consider potential for future replacement or addition of further cells.

Remove all trees from the lagoon and berm area, and around the lagoon for at least 50' to encourage evaporation.


A fence should be built that:

  • completely encloses the lagoon area;
  • is made of woven wire or barbed wire
  • If barbed wire, to be a minimum of 7 strands with the first strand starting 3 inches from the ground and the following strands spaced evenly;
  • is 1.2 m (4') tall; and,
  • has access from one side by a locking gate (any gate should be kept locked);
  • has signs located on each gate with a warning of “NO TRESPASSING — WASTEWATER LAGOON.

of the SEWERAGE SYSTEM Standard Practice Manual Version 2)

So we needed to ensure we are meeting at least these minimum requirements. Also, we wanted to find out what it would take, assuming that it wasn't large enough, to increase it's size so that it could handle the deluge caused by three (eventually) teen-aged girls.

The first thing the we did was had a certified planner visit the site. As I understand it, these individuals aren't allowed to do any construction work. They basically draw up a plan (that is filed with the ministry of health) to indicate what must occur to maintain the system's certification. They may also be contracted periodically to perform maintenance duties (like emptying out the tanks, if you have one).

The plan indicated we should enlarge the lagoon by adding a cell (after testing the adjacent soil), and clear out some of the weeds growing around it (as they interfere with the evaporation caused by sunlight). Once these things are done, the system can be certified. Adding a cell is actually pretty simple - you dig a hole next to the current lagoon, build up some berms, then remove a portion of the old berm.

So next we contacted a ROWP (Registered Onsite Waste Water Practitioner), who is allowed to perform the design, construction and installation, but not allowed to do any work not recommended by a planner. (I guess this makes it harder for two parties to work together at overcharging a customer.) He can easily dig out the new cell, and can also perform the testing to confirm the soil can handle it, as the planner did recommend that a couple test pits be dug.

This is our next step, but we can't do it till the ground is a little less saturated from the snow. If the test pits pass, then a new cell is dug out, and we're all happy. If the pits fail, well, then... that's a bit of a problem. If we can't use the lagoon, we then have to consider a full septic tank system. This is more costly than digging a hole and putting up a fence, by a factor of ten!

I apologize for the dry topic. Though I could write about this ad nauseum, I've restrained myself.


  1. Wow! You guys are really "doing it"!
    Hey, have you looked into the many uses of the Willow? It apparently has excellent purification abilities... perhaps you could plant some in your lagoon. Also they make beautiful live fences....


  2. I really like willows, and I like the idea of live fences. But the regulations would not allow the trees near the lagoon (or within 50'), as they'd interfere with the evaporation.

    But we could put some willows near our 'natural pool' we are thinking of putting in. Turns out you can't swim in a septic lagoon! Who knew?

  3. Not sure if you are aware of it or not. You also have the option of putting in the septic system yourself, under the direction of an engineer. It is the responsability of the planner, not the installer to do the test pits. Without the test pits, a plan is useless. A "professional" can design your system and then simply inspect the work you do. If you've already paid a planner, I would simply take that plan to an engineer and have him do the filing. Prices range from a few hundred to a few thousand for the engineer but that cost can easily be offset by doing the actual work yourself. A ROWP must put in a huge lagoon which often is too large to even keep full. An engineer has the option of a smaller, more efficient lagoon. I suspect that a small one wwould do quite well in your area. I am not an engineer, but a ROWP in training an am sick of seeing people getting hosed by the industry.