Chapter 11.20
NATIONAL POLLUTION DISCHARGE ELIMINATION SYSTEM PROGRAM (NPDES)
Sections
11.20.030 Prohibited discharges.
11.20.040 Allowable discharges.
11.20.050 Conditional discharges.
11.20.060 Illicit connections.
11.20.075 Application of source control best management practices to pollutant-generating sources.
11.20.080 Facility operation and maintenance.
11.20.090 Violations and enforcement.
11.20.010 Purpose.
The purpose of this chapter is to protect the quality of city of Des Moines surface waters and ground waters and Puget Sound by providing minimum requirements for reducing and controlling the discharge of contaminants from industrial, agricultural, commercial, residential, and other land use activities within Des Moines’ jurisdiction from entering the municipal storm water system. Water quality degradation can result either directly from one discharge or through the collective impact of many small discharges. Therefore, this chapter prohibits the discharge of contaminants into surface water, ground water, Puget Sound and the municipal storm water system and outlines preventive measures to restrict contaminants from entering such waters. These measures include the implementation of best management practices as prescribed by this chapter.
This chapter protects the health, safety and welfare of the residents of the city of Des Moines and the integrity of the city’s resources for the benefit of all by minimizing or eliminating water quality degradation, preserving and enhancing the suitability of waters for recreation, fishing, and other beneficial uses and preserving and enhancing the aesthetic quality and biotic integrity of the water. Implementation of this chapter is required under the federal Clean Water Act, 33 U.S.C. 1251 et seq. [Ord. 1463 § 2(1), 2009.]
11.20.020 Definitions.
(1) Use of Words and Phrases. As used in this chapter, unless the context or subject matter clearly requires otherwise, the words or phrases defined in this section shall have the indicated meanings.
(2) “Best management practices” means physical, structural, and/or managerial practices that, when used singly or in combination, prevent or reduce water pollution. Best management practices are listed and described in the King County Stormwater Pollution Prevention Manual, as adopted by reference in DMMC 11.08.060, and King County Surface Water Design Manual as previously adopted in DMMC 11.08.060 and supplemented in DMMC 11.08.070.
(3) “Chapter” means this chapter and any administrative rules and regulations adopted to implement this chapter.
(4) “Clean Water Act” means 33 U.S.C. Section 1251 et seq. as amended.
(5) “Contaminant” means anything which causes or contributes to pollution.
(6) “Director” means the director of the planning, building and public works department.
(7) “Discharge” means to throw, drain, release, dump, spill, empty, emit, or pour forth any matter or to cause or allow matter to flow, run or seep from land or be thrown, drained, released, dumped, spilled, emptied, emitted or poured into the municipal storm water system, surface waters, ground waters or Puget Sound.
(8) “Ground water” means all waters that exist beneath the land surface or beneath the bed of any stream, lake or reservoir or other body of surface water, whatever may be the geological formation or structure in which such water stands or flows, percolates or otherwise moves.
(9) “Hazardous” means any material, including any substance, waste, or combination thereof, which because of its quantity, concentration, or physical, chemical, or infectious characteristics may cause, or significantly contribute to, a substantial present or potential hazard to human health, safety, property or the environment when improperly treated, stored, transported, disposed of, or otherwise managed.
(10) “Hyperchlorinated” means water that contains more than 10 mg/liter chlorine.
(11) “Illicit connection” means any man-made conveyance that is connected to the municipal storm water system that allows the discharge of illicit discharges to the municipal storm water system. Examples include sanitary sewer connections, septic tank discharge pipe connections, floor drains, channels, pipelines, conduits, inlets, or outlets that are connected directly to the municipal storm water system.
(12) “Illicit discharge” means any direct or indirect non-storm water discharge to the municipal storm water system, surface waters, ground waters, or Puget Sound, except as expressly exempted by this chapter.
(13) “Municipal storm water system” means a conveyance or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, manmade channels, or storm drains):
(a) Owned or operated by the city of Des Moines;
(b) Designed or used for collecting or conveying storm water; and
(c) Which is not part of a publicly owned treatment works (POTW). “POTW” means any device or system used in treatment of municipal sewage or industrial wastes of a liquid nature which is publicly owned.
(14) “National pollutant discharge elimination system (NPDES)” means the national program for controlling pollutants from point source discharges directly into waters of the United States under the Clean Water Act.
(15) “National pollutant discharge elimination system permit” means an authorization, license or equivalent control document issued by the Environmental Protection Agency or the Washington State Department of Ecology to implement the requirements of the NPDES program.
(16) “Person” means any individual, partnership, corporation, association, organization, cooperative, public or municipal corporation, agency of the state, or local government unit, however designated.
(17) “Single-family residential activity” means normal activities associated with single-family residential land uses other than home-operated businesses or auto repair activities.
(18) “Storm water” means that portion of precipitation that does not naturally percolate into the ground or evaporate, but flows via overland flow, interflow, channels or pipes into a defined surface water channel, or a constructed infiltration facility.
(19) “Storm water drainage system” means constructed and natural features which function together as a system to collect, convey, channel, hold, inhibit, retain, detain, infiltrate, divert, treat or filter storm water.
(20) “Storm water facility” means a constructed component of a storm water drainage system designed or constructed to perform a particular function, or multiple functions. Storm water facilities include, but are not limited to, pipes, swales, ditches, culverts, street gutters, detention basins, retention basins, constructed wetlands, infiltration devices, catch basins, oil/water separators, sediment basins and modular pavement. Storm water facilities are described in the King County Surface Water Design Manual as previously adopted in DMMC 18.86.330.
(21) “Stormwater Pollution Prevention Manual” means the manual adopted by reference in chapter 11.24 DMMC and prepared by King County that contains best management practices to prevent or reduce pollution.
(22) “Source control best management practice” means a best management practice intended to prevent contaminants from entering surface and storm water or ground water including the modification of processes to eliminate the production or use of contaminants.” Source control best management practices” can be either structural or nonstructural. Structural source control best management practices involve the construction of a physical structure on site, or other type of physical modification to a site. An example of a structural source control best management practice is building a covered storage area. A nonstructural source control best management practice involves the modification or addition of managerial or behavioral practices. An example of a nonstructural source control best management practice is using less toxic alternatives to current products or sweeping parking lots.
(23) “State waste discharge permit” means an authorization, license, or equivalent control document issued by the Washington State Department of Ecology in accordance with chapter 173-216 WAC.
(24) “Surface and storm water” means water originating from rainfall and other precipitation that is found on ground surfaces and in storm water facilities, rivers, streams, springs, seeps, ponds, lakes, and wetlands as well as shallow ground water.
(25) “Treatment best management practice” means a best management practice intended to remove contaminants once they are already contained in storm water. Examples of treatment best management practices include oil/water separators, biofiltration swales and wetponds. [Ord. 1758 § 1, 2022; Ord. 1463 § 2(2), 2009.]
11.20.030 Prohibited discharges.
It is unlawful for any person to discharge any contaminants into the municipal storm water system, surface water, ground water or Puget Sound. Contaminants include, but are not limited to, the following:
(1) Solid waste, trash or debris;
(2) Construction materials;
(3) Petroleum products including but not limited to oil, gasoline, grease, fuel oil, and heating oil;
(4) Antifreeze and other automotive products;
(5) Metals in excess of naturally occurring amounts whether particulate or dissolved form;
(6) Flammable or explosive materials;
(7) Radioactive material;
(8) Batteries;
(9) Acids, alkalis, or bases;
(10) Paints, stains, resins, lacquers or varnishes;
(11) Degreasers and solvents;
(12) Drain cleaners: commercial and household cleaning materials;
(13) Pesticides, herbicides or fertilizers;
(14) Steam cleaning wastes;
(15) Laundry waste, soap, detergent or ammonia;
(16) Swimming pool or spa filter backwash;
(17) Chlorine, bromine and other disinfectants;
(18) Heated water;
(19) Animal waste;
(20) Domestic or sanitary sewage;
(21) Recreational vehicle waste;
(22) Animal carcasses;
(23) Food and food waste including fats, oils, and grease (FOG);
(24) Bark and other fibrous materials;
(25) Collected lawn clippings, leaves or branches;
(26) Silt, sediment, cement or gravel;
(27) Dyes, except as permitted by this chapter;
(28) Chemicals not normally found in uncontaminated water;
(29) Chlorinated swimming pool or hot tub water except as permitted by this chapter;
(30) Discharges from potable water sources which may include but are not limited to: water line flushing, hyperchlorinated water line flushing, fire hydrant flushing, and pipeline hydrostatic test water, except as permitted by this chapter; and
(31) Any hazardous material or waste not listed above. [Ord. 1463 § 2(3), 2009.]
11.20.040 Allowable discharges.
The following types of discharges shall not be considered prohibited discharges for the purpose of this chapter:
(1) Spring water;
(2) Diverted stream flows;
(3) Uncontaminated water from crawl space pumps, foundation drains, or footing drains;
(4) Single-family residential lawn irrigation watering that is commingled with urban storm water;
(5) Pumped ground water flows that are uncontaminated;
(6) Materials placed as part of an approved habitat restoration or bank stabilization project;
(7) Natural uncontaminated surface water or ground water;
(8) Flows from riparian habitats and wetlands;
(9) Collected rainwater that is uncontaminated;
(10) Uncontaminated groundwater that seeps into or otherwise enters storm water conveyance systems;
(11) Air conditioning condensation;
(12) Non-storm water discharges covered by another NPDES permit;
(13) Dye testing using environmentally friendly products for the purpose of testing or tracing source pollution is allowable but requires verbal notification to the city prior to the time of testing; or
(14) Discharges from emergency fire fighting activities. [Ord. 1463 § 2(4), 2009.]
11.20.050 Conditional discharges.
Best management practices shall be applied to any business or residential activity that might result in prohibited discharges as specified in the Stormwater Pollution Prevention Manual. Activities that might result in prohibited discharges include but are not limited to the following:
(1) Potable water, including water from line flushing, hyperchlorinated water line flushing, fire hydrant system flushing, and pipeline hydrostatic test water. Planned discharges shall be dechlorinated to a concentration of 0.1 ppm or less, pH-adjusted if necessary, and in volumes and velocities controlled to prevent resuspension of sediments in the storm water;
(2) Lawn watering or other irrigation, except single-family residential, is permitted using best management practices regarding lawn care and vegetation management;
(3) Dechlorinated swimming pool discharges. The discharges shall be dechlorinated to a concentration of 0.1 ppm or less, pH-adjusted and reoxygenated if necessary, volumetrically and velocity controlled to prevent resuspension of sediments. Swimming pool cleaning wastewater and filter backwash shall not be discharged;
(4) Street and sidewalk wash water, water used to control dust, and routine external building wash down that does not use detergents are permitted; provided, that best management practices are used in accordance to the Stormwater Pollution Prevention Manual as adopted in chapter 11.24 DMMC;
(5) Other non-storm water discharges. The discharges shall be in compliance with the requirements of a storm water pollution prevention plan that is reviewed and approved by the director using best management practices to address such discharges. [Ord. 1463 § 2(5), 2009.]
11.20.060 Illicit connections.
Any connection identified by the director that could convey anything not composed entirely of surface and storm water directly to the municipal storm water system is considered an illicit connection and is prohibited with the following exceptions:
(1) Connections conveying allowable discharges or conditional discharges;
(2) Connections conveying discharges pursuant to an NPDES permit or a state waste discharge permit; and
(3) Connections conveying effluent from on-site sewage disposal systems to subsurface soils. [Ord. 1463 § 2(6), 2009.]
11.20.070 Requirement to prevent, control, and reduce storm water contamination by use of best management practices.
(1) Compliance with this chapter shall be achieved through the use of the best management practices in accordance with the King County “Stormwater Pollution Prevention Manual,” as adopted by reference in DMMC 11.08.060. Any owner/operator responsible for premises which are found to be the source of an illicit discharge will be required to implement, at owner/operator’s expense, the structural and nonstructural best management practices as specified in the manual to prevent the further discharge of contaminants to the municipal storm water system, ground waters, surface waters, or Puget Sound.
(2) Technical Assistance. The City of Des Moines surface water management division will provide, upon reasonable request, available technical assistance materials and information.
(3) In applying the Stormwater Pollution Prevention Manual to prohibited discharges from single-family residential activities, the Director shall use public education and warnings as the primary method of gaining compliance with this chapter and shall not use citations, notice and orders, assessment of civil penalties and fines, or other compliance actions as authorized in this chapter, unless the Director determines:
(a) The discharge from a normal single-family residential activity, whether singly or in combination with other discharges, is causing a significant contribution of contaminants to surface and storm water or ground water; or
(b) The discharge from a normal single-family residential activity poses a hazard to the public health, safety or welfare, endangers any property or adversely affects the safety and operation of City rights-of-way, utilities or other publicly owned or maintained property.
(4) Persons implementing best management practices through another federal, state or local program will not be required to implement the best management practices prescribed in the Stormwater Pollution Prevention Manual, unless the Director determines the alternative best management practices are ineffective at reducing the discharge of contaminants. If the other program requires the development of a storm water pollution prevention plan or other best management practices plan, the person shall make the plan available to the City upon request. [Ord. 1758 § 2, 2022; Ord. 1463 § 2(7), 2009.]
11.20.075 Application of source control best management practices to pollutant-generating sources.
(1) Any person responsible for land uses and/or activities which generate pollutants will be required to implement, at that person’s expense, best management practices (“BMPs”) to prevent the further discharge of pollutants to the municipal storm water system, ground waters, surface waters, or Puget Sound.
(a) Applicable operational source control BMPs shall be required for all pollutant-generating sources.
(b) Structural source control BMPs, or treatment BMPs/facilities, or both, shall be required for pollutant-generating sources if operational source control BMPs do not prevent illicit discharges or violations of surface water, groundwater, or sediment management standards because of inadequate storm water controls.
(c) In cases where the King County Stormwater Pollution Prevention Manual, as adopted by reference in DMMC 11.08.060, lacks guidance for a specific source of pollutants, the Director shall work with the responsible person to implement or adapt BMPs based on the best professional judgement of the Director.
(2) Administration.
(a) The Director shall develop and implement a “source control inventory” which identifies potential pollutant-generating sources that discharge to the municipal storm water system, ground waters, surface waters, or Puget Sound. The inventory shall include, but not be limited to, businesses and/or activities identified in the Western Washington Phase II Municipal Stormwater Permit as potential outdoor pollutant-generating sources.
(b) The Director shall develop and implement a program and procedures for the regular inspection of all potential pollutant-generating sources included in the source control inventory described in subsection (2)(a) of this section. The program shall be administered consistent with the administrative provisions contained in DMMC 11.20.080(5). [Ord. 1758 § 3, 2022.]
11.20.080 Facility operation and maintenance.
The provisions of this section are intended to provide standards and procedures for inspection and maintenance of storm water facilities in Des Moines to provide for an effective, functional storm water drainage system.
(1) Ownership, Operation and Maintenance Requirement.
(a) Public Storm Water Facilities.
(i) Storm Water Facilities in Rights-of-Way or Dedicated Easements or Tracts. The city of Des Moines shall own, operate and maintain all elements of the storm drainage system in the right-of-way and in easements or tracts granted or dedicated to and accepted by the city of Des Moines.
(ii) Existing Storm Water Facilities on Private Property. The city of Des Moines will not acquire or accept (via dedication, grant of easement, or other conveyance) existing components of the storm water conveyance system located on private property, except when the components are needed for city of Des Moines construction projects identified in the capital plan or annual capital improvement program, or when in the best interest of the city as determined by the city council.
(iii) New Storm Water Facilities. The city of Des Moines will accept ownership and responsibility for new retention/detention systems (via dedication, grant of easement, or other covenant) only if all of the following conditions are met:
(A) Public ownership of the system will provide a public benefit;
(B) An easement or dedication of the property is offered by the property owner at no cost;
(C) The system meets city standards;
(D) There is access for city of Des Moines maintenance workers from a public right-of-way;
(E) The city of Des Moines has adequate resources to maintain the system; and
(F) The system serves a subdivision (as opposed to a multifamily or commercial property).
(b) Private Storm Water Facilities. Unless a written maintenance agreement is made between the city and property owner pursuant to DMMC 11.12.070, storm water systems located on private property shall be the responsibility of the owner to operate, inspect, maintain and improve.
(2) Maintenance Responsibility.
(a) All storm water facilities shall be maintained in accordance with this section, the King County Surface Water Design Manual, and the King County Pollution Prevention Manual. Storm water facilities shall be maintained so that they operate as intended. Systematic, routine preventive maintenance is preferred.
(b) Public Storm Water Facilities. The responsibility of the city of Des Moines shall be limited to maintenance and operation of the municipal storm water system, and the city of Des Moines assumes no responsibility for maintenance and operation of private systems other than private systems under a written agreement pursuant to DMMC 11.12.070.
(c) Private Storm Water Facilities. Property owners are responsible for the maintenance, operation or repair of storm water drainage systems and best management practices. Property owners shall maintain, operate and repair these facilities in compliance with the requirements of this section.
(d) New Subdivisions. In new subdivisions, maintenance responsibility for private storm water facilities shall be specified on the face of the subdivision.
(e) Existing Subdivisions. If a private storm water facility serves multiple lots and the responsibility for maintenance has not been specified on the subdivision plat or other legal document, maintenance responsibility shall rest with the homeowners’ association, if one exists, or otherwise with the owners of the properties served by the facility. If owners of the properties served by the facility cannot be located, maintenance responsibility shall rest with the owner(s) of the property on which the facilities are located.
(3) Minimum Maintenance Standards. The following are the minimum standards for the maintenance of storm water facilities:
(a) All storm water facilities shall be inspected at regular intervals and maintained and repaired in accordance with the King County Surface Water Design Manual maintenance requirements, an approved operation and maintenance manual for storm water facilities, or by permits which may be issued by the State Department of Ecology, or the Environmental Protection Agency (EPA), applicable construction standards, and the minimum requirements as stated in the King County Stormwater Pollution Prevention Manual.
(b) Where maintenance and repair is necessary to correct health or safety problems, to prevent harmful materials from entering the storm water system, or to remove harmful materials that have entered the storm water system, such work shall be completed by the owner or operator of the storm water system or storm water facility within 24 hours of discovery of the need for maintenance or repair. When maintenance and repair is found necessary to prevent water quality degradation, such work shall be completed within 14 calendar days of discovery of the need for maintenance or repair. For other related problems, maintenance or repairs shall be completed within 30 calendar days of discovery or repair.
(c) Where lack of maintenance is causing or contributing to a water quality problem, immediate action shall be taken to correct the problem. Within one month, the director or his or her designee shall revisit the facility to assure that it is being maintained.
(d) Should the director have reasonable cause to believe that the situation at a private storm water facility is so adverse or hazardous so as to preclude written notice, he or she may take the measures necessary to eliminate the hazardous situation; provided, that he or she shall first make a reasonable effort to locate the owner before acting. In such instances the owner of the property and/or the person responsible for the maintenance of the facility shall be obligated for the payment of all costs incurred. If costs are incurred and a bond pursuant to this chapter or other city requirement has been posted, the director shall have the authority to collect against the bond to cover costs incurred.
(e) Illicit discharges to the storm water system are prohibited, unless such discharges are authorized in accordance with chapter 173-216 WAC (State Waste Discharge Permit Program) or chapter 173-220 WAC (National Pollutant Discharge Elimination System Program).
(f) Harmful and prohibited materials, as defined in this section, shall not be allowed to enter any storm water system. All such substances shall be stored, handled and disposed in a manner that will prevent them from entering the storm water system. Further, storage, handling and disposal shall be conducted in accordance with chapters 173-303 and 173-304 WAC.
(4) Disposal of Waste from Maintenance Activities. Disposal of waste from maintenance activities shall be conducted in accordance with the Minimum Functional Standards for Solid Waste Handling, chapter 173-304 WAC, guidelines for disposal of waste materials from storm water maintenance activities, and, where appropriate, the Dangerous Waste Regulations, chapter 173-303 WAC.
(5) Administration.
(a) Inspection Program.
(i) The director shall develop and implement a program and procedures for the regular inspection of all public and private storm water facilities in Des Moines. As part of that program, or whenever there is probable cause to believe that a violation of this chapter or article has been or is being committed, the director (or his or her designated inspector) is authorized to inspect all public and private portions of the storm water drainage systems within Des Moines during regular working hours and at other reasonable times to determine compliance with the provisions of this chapter.
(ii) As part of the inspection program, the director shall establish a master inspection and maintenance schedule. Inspections shall be annual, at a minimum. Critical storm water facilities may require a more frequent inspection schedule. If, during an inspection, a facility is found not to be in compliance with the standards as described in this chapter, all subsequent inspection and maintenance intervals shall be scheduled more frequently if determined by the director to be necessary in order to assure future compliance. If, during the course of the inspection program, additional existing storm water facilities are discovered, they shall be added to the master inspection and maintenance schedule.
(b) Entry to Storm Water Facilities. Prior to making any inspections, the director or designated inspector shall present identification credentials, state the reason for the inspection and request entry.
(i) If the property or any building or structure on the property is unoccupied, the director or designated inspector shall first make a reasonable effort to locate the owner or other person(s) having charge or control of the property or portions of the property and request entry.
(ii) If after reasonable effort, the director or designated inspector is unable to locate the owner or other person(s) having charge or control of the property, and has reason to believe the condition of the storm water drainage system creates a risk of imminent harm to persons or property, the inspector may enter.
(iii) If entry is not consented to by the owner or person(s) in control of the property or portion of the property, and no conditions are reasonably believed to exist which create a risk of imminent harm, the director shall obtain a search warrant as authorized by the laws of the state of Washington.
(iv) The director or designated inspector may also inspect the storm water drainage system without obtaining a search warrant, provided the inspection can be conducted while remaining on public property or other property on which permission to enter is obtained.
(6) Inspection and Maintenance Records.
(a) Records for New Facilities. Records of new public or private storm water facilities shall include the following:
(i) As-built plans and locations.
(ii) Findings of fact for any exemption granted by the city of Des Moines.
(iii) Operations and maintenance requirements and records of inspections, maintenance actions and frequencies.
(iv) Engineering reports, if prepared prior to or during construction of the facility.
(b) Records for Existing Facilities. Upon the request of the director or designated inspector, all owners of existing storm drainage systems shall provide the director with all inspection, maintenance and repair records for their facilities, as well as any existing record drawings or diagrams of their storm drainage systems. [Ord. 1463 § 2(8), 2009.]
11.20.090 Violations and enforcement.
Whenever the city finds that an owner/operator has violated or failed to meet a requirement in any provision of this chapter, the city may pursue the code enforcement procedures set forth in chapter 1.28 DMMC. Any violation of this chapter that is deemed by the director to be a threat or potential threat to the public health, safety and welfare may be abated as a nuisance or pursuant to any other applicable local, state or federal law or regulation. Regulation under this chapter shall not serve as a shield to any action under other applicable laws or regulations of the city, state, or United States. [Ord. 1463 § 2(9), 2009.]