a. Any liquids, solids or gases which by reason of their nature or quantity are or may be sufficient, either alone or by interaction with other substances, to cause fire or explosion or be injurious in any other way to the POTW or to the operation of the POTW. Prohibited materials include but are not limited to gasoline, kerosene, naphtha, benzene, toluene, xylene, ethers, alcohols, ketones, aldehydes, peroxides, chlorates, perchlorates, bromates, carbides, hydrides and sulfides.

b. Solid or viscous substances which may cause obstruction to the flow in a sewer or other interference with the operation of the wastewater treatment facilities, such as but not limited to grease, garbage with particles greater than one-half inch in any dimension, animal entrails or tissues, paunch manure, bones, hair, hides or fleshings, whole blood, feathers, ashes, cinders, sand, spent lime, stone or marble dust, metal, glass, straw, shavings, grass clippings, rags, spent grains, spent hops, wastepaper, wood, plastics, tar, asphalt residues from refining or processing of fuel or lubricating oil, mud or glass grinding or polishing wastes.

c. Any wastewater containing toxic pollutants, hazardous wastes as defined by the Resource Conservation and Recovery Act, whether or not they are considered to be hazardous after entering the POTW, or poisonous substances in sufficient quantity, either singly or by interaction with other pollutants, to injure or interfere with any wastewater treatment process, constitute a hazard to humans or animals, create a toxic effect in the receiving waters of the POTW, or exceed the limitation set forth in a categorical standard.

d. Sewage of such a nature and delivered at such a rate as to impair the hydraulic capacity of the system, or any part thereof; normal and reasonable wear and usage excepted.

e. Sewage of such a quantity, quality, or other nature as to impair the strength or the durability of the sewer structures, equipment or treatment works, either by chemical or by mechanical action.

f. Any night soil or septic tank pumpage, except by permit in writing from the general manager at such points and under such conditions as the general manager may stipulate in each permit.

g. Sludge or other material from sewage or industrial waste treatment plants or from water treatment plants, except when authorized by the general manager.

h. Water which has been used for cooling or heat transfer purposes without recirculation, discharged from any system of condensation, air conditioning, refrigeration, or similar use.

i. Water accumulated in excavations or accumulated as the result of grading, water taken from the ground by well points, or any other drainage associated with construction.

j. Any water or wastes containing grease or oil or other substances that will solidify or become discernibly viscous within a temperature range set forth in the rules and regulations promulgated by the general manager.

k. Any wastes that contain a corrosive, noxious, or malodorous material or substance which, either singly or by reaction with other wastes, are capable of causing damage to the system or to any part thereof, of creating a public nuisance or hazard, or of preventing entry into the sewers for maintenance and repair.

l. Any wastes which are unusual in composition, i.e., contain an extremely large amount of suspended solids or BOD; are high in dissolved solids such as sodium chloride, calcium chloride, or sodium sulfate; contain substances conducive to creating tastes or odors in drinking water supplies; otherwise make such waters unpalatable even after conventional water purification treatment; or are in any other way extremely unusual unless the general manager determines that such wastes may be admitted to the system or shall be modified or treated before being so admitted.

m. Any wastes that contain excessive, as determined by the general manager, dye waste or others that are either highly colored or could become highly colored by reacting with any other wastes.

n. Any substance which may cause the POTW's effluent or any other product of the POTW, such as residues, sludges or scums to be unsuitable for reclamation and reuse or to interfere with the reclamation processes. In no case shall a substance discharged to the POTW cause the POTW to be in noncompliance with sludge use or disposal criteria, guidelines or regulations developed pursuant to the Solid Waste Disposal Act, the Resource Conservation and Recovery Act, the Clean Air Act, the Toxic Substances Control Act, the Marine Protection, Research and Sanctuary Act, or more stringent state or local criteria, guidelines, or regulations applicable to the sludge management method being used.

o. Any substance which will cause the POTW to violate its NPDES permit or the receiving water quality standards.

p. Any wastewater having a temperature which will inhibit biological activity in the POTW treatment plant resulting in interference, but in no case wastewater containing heat or capable of creating heat in such amounts that the temperature at the introduction into the POTW treatment plant exceeds 40 degrees Celsius (104 degrees Fahrenheit).

q. Any pollutants, including oxygen demanding pollutants (BOD), etc., released at a flow rate and/or pollutant concentration which will cause pass through or interference. In no case shall a slug discharge have a flow rate or contain concentrations or qualities of pollutants that exceed for any time period longer than 15 minutes more than five times the average 24-hour concentration, quantities, or flow during normal operation.

r. Any wastewater containing any radioactive wastes or isotopes of such half-life or concentration as may exceed limits established by the general manager in compliance with applicable metro district, state or federal regulations.

a. Advise the user of the impact of the contribution on the POTW; and

b. Develop effluent limitations for such user to correct the interference with the POTW.