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SEPTIC OR CENTRAL SEWER IS THERE A BETTER WAY?

Craig Goodwin

NCS Wastewater Solutions

Puyallup, Washington

March 12, 2002

Wastewater management is not a glamorous subject but it remains a core public policy concern.  A decision to sewer or to rely on septic systems will have a significant impact on land use, growth management, drinking water quality, public health, watershed protection, public finance and quality of life issues.  The strategic tradeoffs are complex and often emotional, with passionate constituencies advocating and protecting their cause.

The debate, however, is typically framed in this simple central sewer versus septic tradeoff.  Should we spend the money to add central treatment plant capacity and extend sewer to new areas or instead, reduce density and rely on individual home septic systems?  The end result too often is that conscious deliberative public policy decisions are not made they happen by default.  The cost of expanding sewer treatment capacity and extending collection to new areas is often just too expensive and who will pay for it?  If you are a small community currently without sewer and want to grow, adding central sewer can be virtually impossible.  As a result, we throw up our hands, wait for a grant from heaven and septic reigns.

During the last five years, between 40% and 50% of all new residences were built with septic systems.  In faster growing areas, the percentages are usually much higher.  The greater Atlanta area, for example, is a case in point where nearly all new development in several high growth surrounding counties is on septic.  Is this a problem?  Yes, I believe it is and the legacy problems will grow with time.

How Did We Get Here?

To put it mildly, financing infrastructure growth is a big challenge.  It's expensive and nobody wants to pay for it.  Sewer infrastructure funding must compete with highways, schools, clean water, parks and other important community priorities.  Many communities like the city of Atlanta, have so many problems with their existing sewer system that fixing these problems, let alone accommodating growth, is more than can be done.

Even after the assessment of what developers perceive to be punitive "impact fees", this still doesn't cover the full cost; established residences and businesses will have to pick up some of the tab for growth, further limiting political support.  For many residents, it's a double hit – costing them money and adding to growth and congestion around them.  By denying new sewer, they can stop growth and protect their wallet. 

This leaves developers with a problem build sewer capacity themselves, affording maximum density, or default to septic systems with less density.  100% developer financed private sewers are expensive, if not cost prohibitive, assuming land can be found for land application/disposal and assuming permits can be obtained in reasonable time big ifs in many areas, particularly in my home state of Washington. 

A prospective 1,000 acre golf course community development[1] with no realistic potential for central sewer access will serve to illustrate the tradeoffs.

Despite the potential for higher density, investing in private central sewer is a big stretch.  And even more important than the capital required is the high level of ongoing cash operating costs that will be incurred significantly higher than homeowners typically pay in most areas of the country.  As a result, septic is lower cost, lower risk and much faster to develop.  I also find that it's few developers' dream to be in the sewer business.

Why Is This A Problem?

  1. Septic systems have a history of not being maintained, having high failure rates and being a significant contributor to water quality, environmental and public health problems.  It can be easy to dismiss these problems as immaterial or insignificant, but the problems are real.  I have seen too many cases over the years to dismiss this as unimportant; of untreated raw sewage running down a restaurant parking lot with patrons walking through it on the way to eat dinner, of treatment systems not working and raw sewage in the ditch with kids playing in it, of a day care center with sewage standing in the playground and children all around, of ---------.  It goes on.  The following reported statistics support the significance of the problem:

  1. With the addition of new technology and performance based regulations, septic systems can now be placed in previously un-developable areas.  This increases the risks and will likely make the problem of failures much worse, not better. [7]

  1. As a general rule, once septic, always septic.  My office is full of studies by large engineering firms evaluating how to add sewer to small communities who are currently stymied in their development by lack of sewer and current septic failures.  Virtually without exception, these studies all recommend variations on the "big pipe" solution and none of them are affordable.  Absent a windfall grant, nothing will happen.  We find community after community in a similar bind all across the country. 

The Town of Rainier Washington provides a representative example [8] .  Located about 20 miles southeast of Olympia Washington, Rainier currently has a population of about 1,750 with a total of 616 equivalent residential units.  The Town has an approved Comprehensive Plan for Growth Management, which is designed to accommodate greater density and up to 1,299 equivalent residential units by the year 2020.  The Town, however, is stymied by the lack of sewer infrastructure and concern for contaminating the Town's potable water supply.

Three sewer alternatives were considered, including building their own sewage treatment plant or connecting to either of two existing municipal treatment plants located nearby, with the closest being 6.3 miles away.  Excluding permits the alternatives ranged in cost from $13,586,000 to $14,414,000.  Assuming that all 616 equivalent residential units signed up, under the best case this equates to $22,055 per residence.  When people were surveyed, only 297 (53%) of residences were willing to voluntarily hook up to sewer if they paid no hook-up fee and a $39 per month charge (which wouldn't even cover cash operating costs).

What slim amount of grant money there is available typically goes to the "big" problems (clear cases of high risk to public health and the environment), leaving Rainier and thousands of towns like it across the country stuck and decaying.

The lesson in this is that there is a significant "legacy cost" to pay later down the road for the septic versus sewer decisions we make now. 

  1. Low density development on septic systems contributes to sprawl and sub-optimum land use.  A popular strategy for growth management is to deny access to sewer and thus slow growth.  Montgomery County (Rockville) Maryland is a good example.  It's growing by leaps and bounds fueled by Washington D.C.'s federal government engine.  To control growth, a policy decision was made to not extend sewer beyond specified boundaries.  Outside these sewered boundaries, maximum 1 acre lot densities are allowed and septic systems must be used.

Clearly, the objective is to limit growth.  Using sewer, however, as the blunt instrument to enforce growth management can actually backfire and lead to sprawl.  Figure 1 illustrates an area currently rural [9] .  Figure 2 illustrates this area if developed on septic.  Figure 3 illustrates this same area developed utilizing sewer.  Densities are the same but open space and land utilization are dramatically improved when sewered.  Surface water and groundwater protection are also substantially improved.  Do we really want 1 acre lot sprawl?

Figure 1   Rural Undeveloped

Figure 2   Developed On Septic

Figure 3   Developed On Sewer

What's The Alternative?

An emerging design concept that addresses many of these problems is called Small Community Sewer (also sometimes referred to as Distributed Sewer and Decentralized Sewer).  Following are the critical design elements:

  1. Use of low tech and easy to maintain treatment systems for both commercial and residential applications (e.g., Nibbler high strength wastewater treatment units, Bioclere trickling filters, recirculating gravel filters).  Operators don't have to be there every day.  Monthly or even quarterly inspection intervals are adequate.

  1. Multiple treatment systems placed in strategic areas rather than one central plant, reducing collection costs and making phased development far more feasible and cost effective.

  1. Use of drip irrigation to provide flexibility in drainfield/disposal field location and to provide effective distribution of treated wastewater across larger areas (e.g., natural open space areas, golf course fairways and practice tees, ball fields, soccer fields, playgrounds, etc.).

  1. A management infrastructure provided by either private utilities, private companies who provide small community management services such as NCS backed by performance bonds and/or established public utilities.  In my opinion, to operate effectively, ownership of the sewer system must not be left in the hands of homeowners or homeowner associations.  When this happens, the inherent problems of enforcement action and compelling homeowners to pay for repairs, attribute blame for problems etc. are just too complex.  It's practical to shut down a business but not to evict homeowners.

Utilizing the 750 home golf course community development [10] addressed earlier, the following summarizes how Small Community Sewer stacks up to Central Sewer:

a.     Nibbler pretreatment where needed for high strength sources such as restaurants, supermarkets, golf course clubhouse, etc.

b.     Bioclere trickling filter models 36/30 designed for treating up to 20,000 gallons per day each (approximately 80 homes).  Recirculating gravel filters are often an even more affordable/low maintenance option, but they require a larger footprint and may not be practical in all cases.

c.     Drip irrigation fields for land application located in the golf course, open spaces and in recreational areas.  Each 80 home 20,000 gallons per day increment requires approximately 3.4 acres of irrigation field in the North Georgia clay soils evaluated.

Properly designed, installed and managed, Small Community/Distributed Sewer solves many of the problems inherent in today's Central Sewer versus Septic dilemma:

In addition, when applied to existing communities like Rainier, we don't have to sewer the world, only the areas where we have problems or the greatest need.  As in Rainier, the business community/commercial district typically supports sewer and is willing to pay.  They understand that increased property values that will accrue and see the value of increased commercial business.  Sometimes, the biggest problems are in the commercial district and asking homeowners to pay to fix these problems is a real stretch.  Utilizing small flows treatment technologies like the Nibbler and Bioclere units, which can be installed modularly and in close proximity to the source of waste, it becomes more economically feasible to address these higher priority areas first.

The current septic/central sewer debate often leaves us with two bad choices and policy decisions are made by default.  A third way, what we call Small Community or Distributed Sewer offers an additional set of choices not currently in the mix that can help us solve real problems and contribute to responsible growth management. 

For more information regarding Small Community/Distributed Sewer, contact NCS Wastewater Solutions at (800) 444-2371 or email Craig Goodwin at:

craig@nwcascade.com

Craig Goodwin is General Manager of NCS Wastewater Solutions.  NCS provides turnkey Design/Build/Manage services for small community and commercial development in non-sewered areas across the country with installations now in 27 states and Canada.  NCS also manufactures a broad array of products for the onsite industry including the patented Nibbler high strength wastewater treatment systems.

NCS Wastewater Solutions

P.O. Box 73399

Puyallup, WA  98373

www.ncswastewater.com

Phone: (800) 444-2371   Fax: (253) 840-0877


[1]  Taken from NCS golf course community feasibility study in North Georgia.  Costs may vary significantly from location to location and project to project.  These values, however, appear reasonable representative of comparative costs and order of magnitude differences between alternatives.

[2] Operating costs for advanced treatment in sensitive areas or for reuse can be substantially higher.  Operating costs exclude debt service.

[3]  U.S. Environmental Protection Agency, National Water Quality Inventory Report to Congress (305(b) Report, 1995.

[4]  U.S. Environmental Protection Agency, 1996 Clean Water Needs Survey Report to Congress, September, 1997. (EPA 832/R-97-003).

[5]  U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Shellfish Register, 1995.

[6]  U.S. Environmental Protection Agency, 40 CFR Parts 141 and 142; National Primary Drinking Water Regulations; Ground Water Rule; Proposed Rules, Federal Register, May 10, 2000.

[7]  Operations & Maintenance, Lots of Talk, Where's The Beef?, Craig Goodwin, NCS Wastewater Solutions, University of Washington 11th Northwest On-Site Treatment Short Course, September 15, 2001.

[8] Town of Rainier, Wastewater Scoping Study, G&O 01444, April 2001.

[9] Site illustrations courtesy of Dodson Associates, Lorraine Joubert and the University of Rhode Island Cooperative Extension, Kingston Rhode Island.

[10]  Taken from NCS golf course community feasibility study in North Georgia.  Costs may vary significantly from location to location and project to project.  The values, however, appear reasonably representative of comparative costs and order of magnitude differences between alternatives.