Other States:
WASHINGTON
Population: 5,894,121

Information on the state of Washington is available for the following topics. To review this information, click on the links below.

Contacts| Regulations, Statutes & State Codes | Quick Facts | Septic Stats

Onsite Demonstration Programs | Onsite Management Communities

 

 

Contacts:
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J. Mark Soltman, Supervisor, or
John Eliasson, Wastewater Management Specialist
Washington State Department of Health (WSDOH)
Environmental Health Programs
PO Box 47825
Olympia, Washington 98504-7825
(360) 236-3040 and (360) 236-3041 (respectively)
(360) 236-2261 (fax)

mark.soltman@doh.wa.gov

john.eliasson@doh.wa.gov

http://www.doh.wa.gov/ehp/ts/pubs.htm#wastewater

 

Regulations, Statutes & State Codes:
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Washington State Regulations

Washington Constitutions, Statutes and Codes

On-Site Sewage Systems Regulations
On-Site Sewage Disposal
Chapter 246-272 WAC
May 12, 1995

Guidelines for Gravelless Drainfield Systems
April 5, 1999

Guidelines for Alternating and Dosing Systems
April 5, 1999

Guidelines for the Use of Pressure Distribution Systems
April 12, 2001

Sand Lined Trench Systems
April 5, 1999

Holding Tank Sewage Systems
April 5, 1999

Recommended Standards and Guidance for Alternating Drainfields
April 5, 1999

Guidelines for the Use of Mound Systems
February 15, 2000

Recirculating Gravel Filter Systems
May 15, 2000

Disinfection Methods & Equipment
May 15, 2000

Water Conservation Onsite Wastewater Treatment Systems
May 15, 2000

Guidelines for Intermittent Sand Filters
April 5, 1999

Guidelines for Aerobic Treatment Devices
August 1, 2000

Guidelines for Packed Bed Filters
July 1, 2001

Guidelines for Dosing Gravity Systems
April 5, 1999

Guidelines for Subsurface Drip Systems
January 15, 2002

Guidelines for Stratified Sand Filter Systems
May 15, 2000


Onsite regulations for Washington were last amended in 2000; they are not currently under revision; however, there are plans to begin revision in January 2002. All aspects of Washington onsite sewage system rules and recommended standards and guidance are open for review.

Approved technologies for onsite wastewater treatment and disposal include:
· Conventional gravity flow, gravel-filled drainfields;
· Conventional pressure distribution, gravel-filled drainfields;
· Public domain systems-Intermittent sand filters, recirculating gravel filters, stratified sand filters, and mounds;
· Proprietary systems-gravelless drainfields, aerobic treatment units, packed-bed filters, composting toilets, incineration toilets, vault privies, and sub-surface drip systems.
Washington State currently has provisions in the onsite sewage system rules for experimental systems. Experimenters apply to WSDOH for approval of their proposed experimental testing protocol. Once approved by the State, local jurisdictions may issue permits.

Surface discharge is not an option for onsite disposal systems in Washington.

Drainfield size reductions are allowed under two different schemes: 1) based on effluent quality (10/10/800 gets a 50% reduction), and 2) based on type of technology (some gravelless chamber drainfields may be reduced 20-40% depending upon soil types and manufacturer's sizing recommendation). Those technologies considered for drainfield reductions include gravelless chambers and EZ Flow.

A revolving fund exists to assist homeowners who are replacing a failing or installing a new system. For questions or information, contact Selden Hall, Wastewater Management Specialist, at the address above, or at (360) 236-3043, (360) 236-2261 (fax), or selden.hall@doh.wa.gov

For information about ongoing onsite wastewater demonstration, research, or testing projects in Washington, contact Eliasson (above).

Washington State Code requires management contracts to monitor and maintain all onsite systems, under the jurisdiction of local health departments or district rules and regulations. Local rules and regulations must be in compliance with minimum State onsite sewage system rules, and are subject to review and approval by the State.

Washington State does not track the number of permits issued each year either for new construction or system repair/replacement. Permit records are maintained by local health jurisdictions.

Washington Code defines system failure as a condition of an onsite sewage system that threatens the public health by inadequately treating sewage or by creating a potential for direct or indirect contact between sewage and the public. Examples of failure include:
· Sewage on the surface of the ground;
· Sewage backing up into a structure caused by slow soil absorption of septic tank effluent;
· Sewage leaking from a septic tank, pump chamber, holding tank, or collection system;
· Cesspools or seepage pits where evidence of groundwater or surface water quality degradation exists;
· Inadequately treated effluent contaminating groundwater or surface water; or
· Noncompliance with standards stipulated in the permit.
The reasons for system failure in the state are unknown.

There is State level licensing for designers, and local health agency level licensing for all other onsite wastewater professionals. Licensure or certification to perform site evaluations/inspections requires:
· State-licensed designers for designing an onsite sewage system,
· State-certified local health inspectors for inspecting an onsite sewage system at point of installation, and
· For home sale or property transfer, the licensure/certification varies from local jurisdiction to local jurisdiction.

The Washington State Department of Ecology may be contacted for information about municipal wastewater regulations.


 

Quick Facts:
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Total number of onsite systems: Approximately 700,000.

Number of new systems installed each year: Approximately 25,000.

Failure definition: To be defined as failing, the system must pose a clear public health hazard or
nuisance; direct or indirect contact between sewage and the public.

Number or proportion of systems presently failing: 120,000-375,000; by another account, up
to a third of systems are failing; by still another, 3-5%; these estimates clearly involve different
interpretations of “failing.”

Number or proportion repaired annually: Some 1-4% per annum; 3000-4000 repaired or
replaced annually; by another account, about 0.5% annually. Note however, these numbers
pertain to systems reported and repaired with permits—many are not reported, and instead are
repaired by the homeowner or other non-licensed parties.

Number or proportion replaced annually: The above number includes upgrades.

Number or proportion of repairs or replacements that require alternative technology (e.g.,
sand filters, pressure dosing):
About 30-60% involve some sort of advance over standard septic
tank/drainfield arrangements. Other reports suggest this figure is lower. East of the Cascades
conventional systems are the norm.

Number or proportion of repairs or replacements that require advanced technology (e.g.,
disinfection, nutrient removal):
About 1-2% of those replaced will be highly advanced.

Cost of a conventional septic system installation: $1800-$4500, typically in the range of
$2000-$4000; the alternative systems range $8000-$16,000.

Cost of a centralized sewer tie-in (including fees and cost of the sewer lateral): $10,000-$20,000.

 

Septic Stats:
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TOTAL PERSONS TOTAL HOUSING UNITS PUBLIC SYSTEM DRILLED WELL DUG WELL OTHER PUBLIC SEWER SEPTIC TANK OTHER MEANS
WASHINGTON 4,866,692 2,032,378 1,742,224 231,249 32,283 26,622 1,387,396 630,646 14,336
COUNTIES
ADAMS 13,603 5,263 3,535 1,562 76 90 3,107 2,069 87
ASOTIN 17,605 7,519 7,031 398 29 61 4,755 2,733 31
BENTON 112,560 44,877 38,599 5,830 437 11 32,989 11,741 147
CHELAN 52,250 25,048 19,090 3,978 454 1,526 14,205 10,229 614
CLALLAM 56,464 25,225 18,823 4,829 420 1,153 11,789 13,097 339
CLARK 238,053 92,849 76,589 14,440 1,112 708 61,212 31,329 308
COLUMBIA 4,024 2,046 1,380 450 57 159 1,194 746 106
COWLITZ 82,119 33,304 26,969 4,809 450 1,076 24,576 8,578 150
DOUGLAS 26,205 10,640 8,703 1,382 299 256 5,867 4,618 155
FERRY 6,295 3,239 1,174 1,126 371 568 613 2,323 303
FRANKLIN 37,473 13,664 10,786 2,567 242 69 8,328 5,250 86
GARFIELD 2,248 1,209 766 253 45 145 689 439 81
GRANT 54,758 22,809 16,219 6,290 267 33 13,051 9,501 257
GRAYS HARBOR 64,175 29,932 23,674 4,809 654 795 17,101 12,589 242
ISLAND 60,195 25,860 18,328 6,501 764 267 7,894 17,738 228
JEFFERSON 20,146 11,014 6,885 3,077 397 655 3,819 6,791 404
KING 1,507,319 647,343 629,175 14,444 1,852 1,872 561,678 84,459 1,206
KITSAP 189,731 74,038 58,047 13,391 2,013 587 35,715 37,940 383
KITTITAS 26,725 13,215 8,764 3,776 474 201 7,582 5,503 130
KLICKITAT 16,616 7,213 4,546 2,118 86 463 3,532 3,518 163
LEWIS 59,358 25,487 14,673 8,898 1,141 775 10,197 14,954 336
LINCOLN 8,864 4,607 2,994 1,282 105 226 2,069 2,459 79
MASON 38,341 22,292 11,926 8,471 636 1,259 3,660 17,780 852
OKANOGAN 33,350 16,629 8,007 5,373 2,055 1,194 6,757 8,473 1,399
PACIFIC 18,882 12,404 9,156 2,277 585 386 4,093 8,254 57
PEND OREILLE 8,915 5,404 2,242 2,029 409 724 1,911 3,320 173
PIERCE 586,203 228,842 206,162 19,802 1,480 1,398 155,415 72,588 839
SAN JUAN 10,035 6,075 3,343 2,016 490 226 1,308 4,467 300
SKAGIT 79,555 33,580 26,588 4,880 1,035 1,077 18,532 14,547 501
SKAMANIA 8,289 3,922 2,340 820 75 687 717 3,055 150
SNOHOMISH 465,642 183,942 165,332 11,462 5,515 1,633 126,719 56,342 881
SPOKANE 361,364 150,105 135,494 12,400 1,216 995 99,654 49,837 614
STEVENS 30,948 14,601 6,296 4,704 1,777 1,824 4,161 9,792 648
THURSTON 161,238 66,464 47,544 17,077 1,063 780 27,798 38,119 547
WAHKIAKUM 3,327 1,496 1,007 156 103 230 318 1,178 0
WALLA WALLA 48,439 19,029 15,864 2,824 136 205 13,696 5,149 184
WHATCOM 127,780 55,742 46,029 6,119 2,106 1,488 35,805 19,453 484
WHITMAN 38,775 14,598 11,882 2,146 212 358 11,531 2,960 107
YAKIMA 188,823 70,852 46,262 22,483 1,645 462 43,359 26,728 765

 

Onsite Demonstration Programs:
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Washington On-Site Sewage Association (WOSSA, the training center cited below) runs a
National Onsite Demonstration, Phase II, site; and also was awarded an EPA Small Flows
grant to help solve wastewater problems in the town of Burnett through the installation of
alternative technologies in use elsewhere around the U.S.

Onsite Management Communities:
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Bremerton Kitsap County
Clark County
Cowlitz County
Island County
Jefferson County
Mason County
Skagit County
Skamania County
Snohomish County
Southwest Washington Health District
Thurston County
Tacoma - Pierce County H.D