15.16.090 Prohibited, Allowable, and Conditional Discharges and Connections.
A. Definitions. The following definitions shall be applicable to this section:
1. AKART – All Known, Available, and Reasonable Methods of Prevention, Control, and Treatment. See also the State Water Pollution Control Act, RCW 90.48.010, and RCW 90.48.520.
2. “Ground water” means water in a saturated zone or stratum beneath the surface of the land or below a surface water body.
3. “Hazardous materials” 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.
4. “Hyperchlorinated” means water that contains more than ten (10) mg/L chlorine.
5. “Illicit discharge” means any direct or indirect non-stormwater discharge to the City’s storm drain system, except as expressly exempted by this chapter.
6. “Illicit connection” means any man-made conveyance that is connected to a municipal separate storm sewer without a permit, excluding roof drains and other similar type connections. Examples include sanitary sewer connections, floor drains, channels, pipelines, conduits, inlets, or outlets that are connected directly to the municipal separate storm sewer system.
7. “Municipal separate storm sewer system” (MS4) means a conveyance or system of conveyances, including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains, which are:
a. Owned or operated by the City of Snohomish;
b. Designed or used for collecting or conveying stormwater;
c. 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); and
d. Not a combined sewer. (“Combined sewer” means a system that collects sanitary sewage and stormwater in a single sewer system.)
8. “National Pollutant Discharge Elimination System (NPDES) Stormwater Discharge Permit” means a permit issued by the Environmental Protection Agency (EPA) (or by the Washington Department of Ecology under authority delegated pursuant to 33 USC Section 1342(b)) that authorizes the discharge of pollutants to waters of the United States, whether the permit is applicable on an individual, group, or general area-wide basis.
9. “Non-stormwater discharge” means any discharge to the storm drain system that is not composed entirely of stormwater.
10. “Person” means any individual, association, organization, partnership, firm, corporation, or other entity recognized by law and acting as either the owner of a premises or as the owner's agent.
11. “Pollution” means any pollutants which cause or contribute to pollution. Pollutants may include, but are not limited to: paints, varnishes, and solvents; oil and other automotive fluids; nonhazardous liquid and solid wastes and yard wastes; refuse, rubbish, garbage, litter, or other discarded or abandoned objects and accumulations, so that same may cause or contribute to pollution; floatables; pesticides, herbicides, and fertilizers; hazardous substances and wastes; sewage, fecal coliform, and pathogens; dissolved and particulate metals; animal wastes; wastes and residues that result from constructing a building or structure; and noxious or offensive matter of any kind.
12. “Source control BMP” shall mean a structure or operation intended to prevent pollutants from coming into contact with stormwater through physical separation of areas or careful management of activities that are sources of pollutants. Structural source control BMPs are physical, structural, or mechanical devices or facilities that are intended to prevent pollutants from entering stormwater. Operational source control BMPs are non-structural practices that prevent or reduce pollutants from entering stormwater.
13. “Storm” or “stormwater drainage system” means publicly owned facilities, including the City’s municipal separate storm sewer system, by which stormwater is collected and/or conveyed, including but not limited to any roads with drainage systems, municipal streets, gutters, curbs, inlets, piped storm drains, pumping facilities, retention and detention basins, natural and human-made or altered drainage channels, reservoirs, and other drainage structures.
14. “Stormwater” means runoff during and following precipitation and snowmelt events, including surface runoff and drainage.
15. “Stormwater pollution prevention plan (SWPPP)” means a document which describes the best management practices and activities to be implemented by a person to identify sources of pollution or contamination at a premises and the actions to eliminate or reduce pollutant discharges to stormwater, stormwater conveyance systems, and/or receiving waters to the maximum extent practicable.
B. Prohibited Discharges.
1. No person shall throw, drain, or otherwise discharge, cause or allow others under his/her control to throw, drain or otherwise discharge into the municipal storm drain system any materials other than stormwater.
2. Examples of prohibited contaminants include but are not limited to the following:
a. Trash or debris.
b. Construction materials.
c. Petroleum products including but not limited to oil, gasoline, grease, fuel oil, and heating oil.
d. Antifreeze and other automotive products.
e. Metals in either particulate or dissolved form.
f. Flammable or explosive materials.
g. Radioactive material.
i. Acids, alkalis, or bases.
j. Paints, stains, resins, lacquers, or varnishes.
k. Degreasers and/or solvents.
l. Drain cleaners.
m. Pesticides, herbicides, or fertilizers.
n. Steam cleaning wastes.
o. Soaps, detergents, or ammonia.
p. Swimming pool cleaning wastewater or filter backwash.
q. Chlorine, bromine, or other disinfectants.
r. Heated water.
s. Domestic animal wastes.
u. Recreational vehicle waste.
v. Animal carcasses.
w. Food wastes.
x. Bark and other fibrous materials.
y. Lawn clippings, leaves, or branches.
z. Silt, sediment, concrete, cement, or gravel.
aa. Dyes, unless approved by the City.
bb. Chemicals not normally found in uncontaminated water.
cc. Any other process-associated discharge except as otherwise allowed in this section.
dd. Any hazardous material or waste not listed above.
C. Allowable Discharges. The following types of discharges shall not be considered illegal discharges for the purposes of this chapter unless the City determines that the type of discharge, whether singly or in combination with others, is causing or is likely to cause pollution of surface water or ground water:
1. Diverted stream flows.
2. Rising ground waters.
3. Uncontaminated ground water infiltration – as defined in 40 CFR 35.2005(20).
4. Uncontaminated pumped ground water.
5. Foundation drains.
6. Air conditioning condensation.
7. Irrigation water from agricultural sources that is commingled with urban stormwater.
9. Uncontaminated water from crawl space pumps.
10. Footing drains.
11. Flows from riparian habitats and wetlands.
12. Non-stormwater discharges authorized by another NPDES or state waste discharge permit.
13. Discharges from emergency fire fighting activities.
D. Conditional Discharges. The following types of discharges shall not be considered illegal discharges for the purposes of this chapter, if they meet the stated conditions, or unless the City determines that the type of discharge, whether singly or in combination with others, is causing or is likely to cause pollution of surface water or ground water:
1. Discharges from potable water, including water from water line flushing, hyperchlorinated water line flushing, fire hydrant system flushing, and pipeline hydrostatic test water. These planned discharges shall be dechlorinated to a total residual chlorine concentration of 0.1 ppm or less, pH-adjusted, if necessary and in volumes and velocities controlled to prevent re-suspension of sediments in the stormwater system.
2. Lawn watering and other irrigation runoff. These types of discharges shall be permitted if the amount of runoff is minimized through water conservation efforts.
3. Dechlorinated swimming pool, spa and hot tub discharges. These discharges shall be dechlorinated to a total residual chlorine concentration of 0.1 ppm or less, pH-adjusted and reoxygenized if necessary, volumetrically and velocity controlled to prevent resuspension of sediments in the stormwater system. Discharges shall be thermally controlled to prevent an increase in temperature of the receiving water. Swimming pool cleaning wastewater and filter backwash shall not be discharged to the stormwater system.
4. Street and sidewalk wash water, water used to control dust, and routine external building wash down that does not use detergents. These discharges shall be permitted, if the amount of street wash and dust control water used is minimized. At active construction sites, street sweeping must be performed prior to washing the street.
5. Non-stormwater discharges covered by another NPDES permit. These discharges shall be in full compliance with all requirements of the permit, waiver, or order, and other applicable laws and regulations.
6. Other non-stormwater discharges. These discharges shall be in compliance with the requirements of a stormwater pollution prevention plan (SWPPP) reviewed and approved by the City, which addresses control of such discharges by applying AKART to prevent contaminants from entering surface or ground water.
E. Prohibited Connections.
1. The construction, use, maintenance, or continued existence of illicit connections to the stormwater system is prohibited.
2. This prohibition expressly includes, without limitation, illicit connections made in the past, regardless of whether the connection was permissible under law or practices applicable or prevailing at the time of connection.
3. A person is considered to be in violation of this section if the person connects a line conveying sewage to the MS4 or allows such a connection to continue. (Ord. 2440, 2022)