Onsite Sewerage System Design

This page contains links and information relevant to sewerage system design courses, it was originally developed for the old ES930 planning course given by Royal Roads University and WOWTC but is generally applicable to design. For PDF files, right click and choose "save as".



Pressure Distribution Worksheets

Useful web links

Also take a look at the Installation page and Drawing page


Contact Ian Ralston


These worksheets are intended to assist with the planning of pressure distribution and mound systems, based upon methods used by Converse and by Washington State. Please note that the tables referenced are produced by Washington State and included by permission or are as included in Converse's paper as referenced below. Please let me know if you have any comments on the worksheets or would like to suggest a modification. Note that the worksheets do not at all times comply with the 2005 BC Standard Practices Manual--although they do comply with industry standard practice, so use your own judgment.

These are PDF files. Right click on the links and choose "save as", then you will have them on your computer to use.

Inputs for system design worksheet, this is a one page summary sheet to gather the necessary inputs for design (Daily Design Flow, soil type, HLR and LLR and AIS)--all based on the SPM. This is helpful in gathering information to input to the Pressure Distribution Worksheet or Sand Mound Worksheet, or to use directly for gravity or other system design. Design Inputs worksheet, metric only--from SPM appendix C.

Pressure Distribution Worksheet. From SPM appendix. Has all the tables and instructions. Includes the new float setting worksheet in feet.

Short form worksheet, this is the version for day to day use as part of a record of system design (without tables and instructions), includes float setting worksheet in inches. Use this WITH the long form worksheet (above) which gives instructions and has the tables.

Tank float setting worksheets are available as a separate sheet, see the ES940 page. Note the new recommendation for reserve volume at 15% of Design Flow and Alarm Reserve Volume at 50% (minimum) of Daily Design Flow. For Timed dosing use the timed dosing worksheet (use the normal tank worksheet to determine the V factor for the tank first). PDF file of the text part of the ES930 presentation on timed dosing (created after March 2006 class).

Sand mound worksheet. From SPM appendix. Based on Converse and Washington State approach and diagrams. Use this with the Washington State Mound Guidelines and the instructions in the Wisconsin Mound Paper as in the course manual.

Pressure Distribution Network Design by Converse.
This covers the technique as expanded on by the Pressure Distribution design worksheet, and is referred to in the worksheet by the initials "PD". This is a PDF file.

Pressure Distribution Design from Washington State.
This is used in the course (reprinted in the handouts) and is referred to in the worksheet as "WS", it includes the tables required to use the worksheet. This is a PDF file.

Soil profile record sheet, as provided in the 2007 SPM.

Spreadsheet for selection of design inputs using the 2005 SPM. Note that the blue cells are for inputs, other cells are locked. We will be creating an updated version for the 2007 SPM. File is in Excel 2007 macro enabled format, you must enable the macros for it to work. This is a work in progress, and is provided for interest not for anyone to rely on as a design tool. Use this at your own risk and do not substitute it for proper design input analysis. If you want to save the results, save it to your computer rather than using in the web browser. Please send any comments on improvements that are needed. This spreadsheet and the formulae it contains are copyright to TRAX Developments Ltd.


Useful web links

This page contains links to various websites containing information relevant to the ES930 course, or containing links to such information. Please note that their inclusion here does not suggest that the information has been checked for validity or for relevance to the BC environment, nor does it suggest any endorsement of companies or products mentioned.

Some of the documents are as links to PDF files, these I suggest you right click and choose to "save as" somewhere on your computer to keep them for future reference. Other links open in a new window.

If you have a link that you think should be here, please email me at webmaster@traxdev.com

If you are short of time, as a minimum visit the Washington State site, download the Pressure Distribution documents and mound design worksheets above and obtain the EPA manual.


General sites

Acrobat Reader (for reading and converting PDF files).

Canadian Onsite Technical Resource Association, COTRA

BC Sewerage System Regulation at Ministry of Healthy Living and Sport web site, as xml.

2007 Version 2 BC Standard Practice Manual and appendices at Ministry of Healthy Living and Sport web site, as PDF. The old Version 1 SPM (2005) and amendment is no longer available there and is copied here for your convenience.

US Environmental Protection Agency main site for Septic Systems. This has a large number of useful publications, including the EPA manual referenced in the ES930 course:
Onsite Wastewater Treatment Systems Manual As PDF (note that this is the whole manual -- a 20MB download). There is also the older EPA manual, which is still of some interest, particularly as it is the one used by Washington State. The publications page is here. where you can download sections of the manual.

Washington State Department Of Health Wastewater Management Publications (RS&Gs)
Referred to at many points in the ES930 course this site contains links to a number of useful design guideline documents and technical reviews from the Technical Review Committee . Check out the Nitrogen reduction report (PDF).

The SSWMP Catalogue:
Our Complete Publications List from The University of Wisconsin-Madison Small-Scale Waste Management Project which is where Tyler and Converse work. There are various PDF documents available on a sub page.

Alberta Private Sewage Systems Standard of Practice 1999 Handbook
This site contains useful guidelines for system design, with some very simplified worksheets.

BCWWA papers on onsite systems, as PDF. Useful information on freezing conditions and other design considerations.

Nova Scotia CWRS Web Site
This includes information on the Pask In Situ Permeameter (see below for Wyoming site with online copy of Finnemore's paper), links to the Mounding and Nitrate movement software and the Sloping Sand Filter.

National Small Flows Clearinghouse
Has a large archive of publications.

Delaware ground water discharges section
Another site with design guidelines, includes a section on sand lined trenches.

Center for Decentralized Wastewater Management (CDWM), Tennessee.

BC Ministry of Healthy Living and Sport

BCOSSA and BCOSSA Technical Review Committee (TRC)

Wake County's Well, Wastewater and Development division with info on their pressure manifolds.

Publications of the Headquarters, United States Army Corps of Engineers -- all sorts of technical manuals...

Sewage Wiki page (and sewage treatment)--add your own information

Open office office suite, works well and serves to mimic and replace MS Office. Free.

Cute FTP serves for creating pdf prints of documents, useful for keeping electronic versions and sharing. Works as a printer service. Free.



BC Standard Practice Manual and TRC Technical Bulletins

In BC the Ministry of Healthy Living and Sport provide a manual of "Sewerge System Standard Practice" which provides guidelines and standards for sewerage system (septic system) design, construction, maintenance. This manual is edited for the Ministry by the BCOSSA TRC (Technical Review Committee). The manual is continuously updated, the current version is Version 2, September 2007. This is available on the BCOSSA website and the Ministry website, or download as pdf here: BC SPM V2 (4.6MB PDF)and SPM Appendices (1.9MB PDF) (Large PDF files, open in a new window, right click and select "save as" to download). Note that the appendices include the worksheets.

The BCOSSA Technical Review Committee (TRC) provides technical support to the SPM, and as part of that publishes Technical Bulletins. The Technical Bulletins to the SPM are intended to provide explanation and to answer "FAQs". These are maintained on the TRC part of the BCOSSA website, and are copied here for convenience (all PDF files, open in a new window), right click and select "save as" to download:

Directory of links sites

On-Site Wastewater Information Sources and Links from CWRS


Soils and soil loading rates, pollution control

There is considerable confusion apparent amongst industry and regulators over this issue at present. Review of the literature demonstrates the difficulty of dealing with various loading rates developed in various areas with various safety factors (built into either the loading rates themselves or into the flows to be used with them). Thus loading rates should be approached with caution, whether based on tables or formulae, and only used once one understands the flows and/or safety factors they are intended for, as well as the environmental conditions in the area covered. The Washington State Technical Review of these issues settled on Tyler's work as the most comprehensive, and his papers have the great advantage of clearly stating the flows to be used with the loading rates. The EPA manual also contains useful information on flows and choice of safety factors.

Designing with Soil: Development and Use of a Wastewater Hydraulic Linear and Infiltration Loading Rate Table.
E. Jerry Tyler and Laura Kramer Kuns. Presented at NOWRA 2000 Proceedings. November 2000.
Link to PDF file.

Hydraulic Wastewater Loading Rates to Soils.
E. Jerry Tyler (2001) In: On-site Wastewater Treatment, K. Mancel (ed.)

Washington State technical review committee, HLR and LLR as PDF documents. Also a review of Organic (Mass) Loading Rates and residential flow rates.

High permeability soils are a particular problem area, see a review by the WS technical review cttee. (PDF document).

Wyoming has an interesting spreadsheet program for calculating nitrate impact, an online copy of Finnemore's paper on mounding (used as the basis for the NS mounding program) and papers on nitrate impacts and water quality impacts.

GeotechniCAL is where ground engineering meets education technology. (CAL stands for computer-assisted learning.), site with information on soil mechanics presented in help file format.

Journal article on dynamic penetrometer, including formulae and drawing, as PDF

A site on the achievements of Henry Philibert Gaspard Darcy, (1803-1858). The discoverer of Darcy's Law for flow in porous media.

Sodium content of laundry detergents (sadly, from Australia).

Field Book for Describing and Sampling Soils NRCS (USDA).

Permeameter and infiltrometer information:


Pressure Distribution systems

Center For Efficiency and Renewable Energy site has posted on it Winkler Et Al's pressure distribution spreadsheet (go down the page to "Wastewater Research"), plus some other interesting publications in the area.

Pressure Distribution Network Design by Converse.
This covers the technique as expanded on by the Pressure Distribution design worksheet, and is referred to in the worksheet by the initials "PD". This is a PDF file.

Sand Lined Trench Systems, the Washington State guidelines as referenced in the course. PDF file. Also see the Dewlaware sand lined trench diagram (PDF).

Intelligent Valve Monitor for KRain series 6000 Hydrotek valves, being developed in PEI.

Pressure manifold design spreadsheet for pressure distribution to gravity system, right click and choose "save as" to save to your computer. I have not checked this one...


Wisconsin mound (sand mound)

See also the CWRS web site above for the sloping sand filter.

Wisconsin Mound basic description

Wisconsin Mound Soil Absorption System: Sitting, Design and Construction Manual (Revised Jan. 2000)
This is a link to the SSWMP document by Converse as PDF .

The Washington State Mound Design guidelines (includes the mound design worksheet and diagrams as used in the course) this is the new corrected version. A PDF document.

Mound Systems for On-site Wastewater Treatment Sitting, Design and Construction in Ohio


Manufacturers, treatment plants etc.

Glendon Biofilter
An interesting option for small sites this is essentially an upflow sand filter with integrated disposal to soil.

A sequencing Batch Reactor. Includes an animation of the process.

Copa MBR Technology, microfiltration/membrane bioreactor example.

Zenon membrane filtration, example at Kamploops water treatment plant.

Infiltrator Systems Inc.--technical information page.



Waterloo Biofilter, an example of attached growth aerobic treatment plant.


Drip irrigation

Geoflow web site includes useful links to various publications, including the North American Wetlands paper on drip dispersal in freezing climates. (direct link to the paper as a PDF file). Here you can also download the Geoflow design manual and spreadsheets.

Washington State Drip Irrigation Design Guidelines as PDF. Includes useful guideline for sizing pump chambers for timed dosing.

Center for Decentralized Wastewater Management (CDWM), Tennessee. Guidelines for Drip. Very comprehensive review of current drip irrigation technology and practice.

North American Wetlands Engineering


Drip tech

American Onsite



North American Wetlands Engineering

EPA Constructed Wetlands

South Dakota Recommended Design Criteria fo Artificial Wetland Systems

Individual Residence Wastewater Wetland Construction in Indiana

Wet Kit, Canadian Wetland Tools


Pipes and plumbing. hydraulics

See ES940 page also

An apprentices handbook for plastic pipes, as PDF.

A pipe head loss calculation program.

Vinidex PVC pressure pipe head loss calculations based on the Colebrook-White formula.

Lasco have a handy water hammer calculator

Solving the Colebrook White Equation for Friction Factors article, includes some VBA macros for spreadsheets

Some flow calculators:



Currently not permitted under standard practice. However, here are a couple of sites with some information.

Oasis design, various greywater information

Information site on greywater (basic)



Contact us:
E-mail us or call Ian Ralston at 250-246-4774
TRAX Developments Ltd., Box 9-6, Thetis Island, British Columbia, V0R 2Y0, Canada.