Illinois Administrative Code

Section 604.230 Groundwater Quantity a) A community water supply must determine groundwater source adequacy by the amount of water produced by each well pumping within its calculated safe yield. b) Multiple Well Systems: When multiple wells are used, the combined delivery must eq…

Section 604.235 Groundwater Quality a) Each community water supply using groundwater must collect and analyze one sample per well per month for total coliform bacteria. The analysis must be performed by a certified laboratory. 1) If a routine sample result is total coliform-posit…

Section 604.240 General Well Construction a) Drilling fluids and additives must not impart any toxic substance to the water or promote bacterial contamination. b) Minimum protected depths of drilled wells must provide watertight construction to exclude contamination and seal off …

Section 604.245 Well Testing and Records a) The specific capacity of the production well must be determined by a drawdown test before the well is placed in service. b) Aquifer property data must be: 1) determined by using published values of transmissivity and hydraulic conductiv…

Section 604.250 Aquifer Types and Construction Methods a) Sand or Gravel Wells 1) Unless otherwise approved by the Agency under Section 604.145(b), the permanent casing and grout must extend at least 25 feet below the original ground elevation. 2) If a temporary or a surface casi…

Section 604.255 Well Pumps, Discharge Piping, and Appurtenances a) Where line shaft pumps are used: 1) the casing must be firmly connected to the pump structure or have the casing inserted into a recess extending at least one-half inch into the pump base; 2) the pump foundation a…

Section 604.300 Purpose The purpose of the following requirements is to facilitate protection of source water quality and quantity.

Section 604.305 Source Water Protection Plan Requirement and Contents Each community water supply that treats surface or groundwater as a primary or emergency supply of water must develop a source water protection plan that contains the following minimum elements: a) a vision sta…

Section 604.310 Vision Statement The vision statement must include the following: a) the community water supply's policy and commitment to protecting source water; b) an explanation of the community water supply's resources to protect source water; c) an explanation of the barrie…

Section 604.315 Source Water Assessment a) The source water assessment must contain the following information: 1) a statement of the importance of the source water; 2) a list of water supplies that obtain water from this community water supply; 3) a delineation of all sources of …

Section 604.320 Source Water Protection Plan Objectives The source water protection plan must contain a list of the community water supply's objectives for protecting source water. These objectives can include meeting the requirements of any of the Sections in this Subpart, inclu…

Section 604.325 Action Plan In the action plan, the community water supply must identify the actions needed to achieve the community water supply's objectives determined under Section 604.320. The action plan must include the following: a) descriptions of all projects, programs, …

Section 604.330 Submission a) A community water supply that first commenced construction after July 26, 2019, must develop and submit a source water protection plan simultaneously with the construction permit application. b) A community water supply in existence as of July 26, 20…

Section 604.335 Agency Approval The Agency, not later than 45 days after the receipt of the source water protection plan, will either approve or disapprove the plan. If the Agency takes no action within the 45 days, the community water supply may deem the plan approved. A communi…

Section 604.340 Evaluation and Revision The community water supply must review, and revise as necessary, its source water protection plan no less frequently than every five years. If the community water supply revises its source water protection plan, it must submit the plan to t…

Section 604.400 General Requirements for Aeration a) All aerators, except those discharging to lime softening or clarification plants, must be protected from contamination by birds, insects, wind borne debris, rainfall and water draining off the exterior of the aerator. Screens m…

Section 604.405 Forced or Induced Draft Aeration Forced or induced draft aeration devices must be designed to: a) include a blower with a weatherproof motor in a tight housing and screened enclosure; b) insure adequate counter current of air through the enclosed aerator column; c…

Section 604.410 Spray Aeration Spray aeration design must provide: a) a hydraulic head of between 5 and 25 feet; b) nozzles, with the size, number, and spacing of the nozzles being dependent on the flow rate, the space, and amount of head available; c) nozzle diameters in the ran…

Section 604.415 Pressure Aeration a) Pressure aeration may be used for oxidation purposes only. This process is not acceptable for the removal of dissolved gases. b) Filters following pressure aeration must allow for the release of air. c) Pressure aeration must be designed to 1)…

Section 604.420 Packed Tower Aeration a) Packed tower aeration (PTA) may be used for removing compounds with a Henry's Constant greater than 100 atm mol/mol at 120° C. Compounds with a Henry's Constant less than 10 may not be removed by PTA. For Henry's Constant values between 10…

Section 604.425 Other Methods of Aeration Other methods of aeration may be used if applicable to the treatment needs. The treatment processes must be designed to meet the particular needs of the water to be treated and must be approved by the Agency. Such methods include: a) spra…

Section 604.500 General Clarification Requirements a) All community water supplies designed to treat surface water must have a minimum of two clarification units. The clarifiers must be capable of meeting the plant design capacity with one clarifier removed from service. b) For c…

Section 604.505 Coagulation a) For purposes of this Section, coagulation is a process using coagulant chemicals and mixing by which colloidal and suspended material are destabilized and agglomerated into settleable or filterable flocs, or both. b) For community water supplies tre…

Section 604.510 Flocculation a) For purposes of this Section, flocculation is a process to enhance agglomeration or collection of smaller floc particles into larger, more easily settleable or filterable particles through gentle stirring by hydraulic or mechanical means. b) Basin …

Section 604.515 Sedimentation For purposes of this Section, sedimentation is a process that allows particles to settle by gravity and typically precedes filtration. The detention time for effective clarification is dependent upon a number of factors related to basin design and th…

Section 604.520 Solids Contact Unit a) Adequate piping with sampling taps must be provided to allow for the collection of samples from various depths of the units. b) Chemical Feed. Chemicals must be satisfactorily mixed in accordance with Section 604.1100(b). c) The Agency may r…

Section 604.525 Tube or Plate Settlers a) Settler units consisting of variously shaped tubes or plates installed in multiple layers and at an angle to the flow may be used for sedimentation, following flocculation. b) Tube or plate settlers must meet the following requirements: 1…

Section 604.530 Other High Rate Clarification Processes The Agency may approve high rate clarification processes upon a demonstration of satisfactory performance under on site pilot plant conditions or documentation of full-scale plant operation with similar raw water quality con…

Section 604.600 Filtration a) Application of any one type of filter must be supported by water quality data representing a reasonable period of time to characterize the variations in water quality. The Agency may require pilot treatment studies to demonstrate the applicability of…

Section 604.605 Rapid Rate Gravity Filters a) The use of rapid rate gravity filters requires pretreatment. b) For community water supplies treating surface water, groundwater under the direct influence of surface water, or using lime soda softening treatment, unless otherwise app…

Section 604.610 Rapid Rate Pressure Filters a) Pressure filters must not be used in the filtration of surface water, groundwater under the direct influence of surface water, or water treated by lime soda softening. b) The rate of filtration must not exceed 4 gal/min/ft2 of filter…

Section 604.615 Deep Bed Rapid Rate Gravity Filters Deep bed rapid rate gravity filters refers to rapid rate gravity filters with filter material depths equal to or greater than 48 inches. Filter media sizes are typically larger than those listed in Section 604.605(f)(4). a) Befo…

Section 604.620 Biologically Active Filtration Biologically active filtration refers to the filtration of surface water or a groundwater with iron, manganese or significant natural organic material, which includes the establishment and maintenance of biological activity within th…

Section 604.700 Disinfection Requirement a) Disinfection, in addition to continuous chlorination, is required for all sources utilizing surface water, groundwater under the direct influence of surface water, groundwater obtained from unconfined fractured bedrock, groundwater with…

Section 604.705 Chlorination Equipment a) Procedure for Submitting Plans and Specifications − Design documents for chlorination must be prepared and submitted in accordance with 35 Ill. Adm. Code 602. b) Chlorination equipment must: 1) be large enough to satisfy the immediate chl…

Section 604.710 Points of Application Provisions must be made for the capability to add a disinfectant into or prior to any aeration, settling, or filtration process, unless the process involves biological treatment, in which case the disinfectant must be added after the biologic…

Section 604.715 Contact Time a) Unless otherwise approved by the Agency under Section 604.145(b), a minimum chlorine contact time of 60 minutes must be provided at all plants treating surface water, groundwater under the direct influence of surface water, groundwater with basins …

Section 604.720 Inactivation of Pathogens a) At plants treating surface water or groundwater under the direct influence of surface water, a disinfectant must be added to provide: 1) a minimum 0.5-log inactivation of Giardia lamblia cysts; and 2) a minimum 2-log inactivation of vi…

Section 604.725 Residual Chlorine a) A minimum free chlorine residual of 0.5 mg/L or a minimum combined chlorine residual of 1.0 mg/L must be maintained in all active parts of the distribution system at all times. b) Community water supplies must monitor chlorine residual to dete…

Section 604.730 Continuous Chlorine Analyzers Community water supplies that rely on chlorination for disinfection under Section 604.700(a) must have continuous chlorine residual analyzers with alarm capability that alerts the community water supply if chlorine residuals at the en…

Section 604.735 Chlorinator Piping a) Cross-Connection Protection 1) The chlorinator piping must be designed to prevent contamination of the treated water. 2) For all systems required to disinfect under Section 604.700, piping must be arranged to prevent backflow or back-siphonag…

Section 604.800 Lime or Lime-soda Process a) Design standards for rapid mix, flocculation and sedimentation are in Subpart E. b) When split treatment is used, an accurate means of measuring and splitting the flow must be provided. c) Before installation of lime or lime-soda proce…

Section 604.805 Cation Exchange Process a) Pre-treatment under Section 604.1010(b) or (c) is required when the content of iron, manganese, or a combination of the two is 1 mg/L or more. b) Design requirements must provide: 1) automatic regeneration based on the volume of water so…

Section 604.900 General Stabilization Requirements a) Water distributed by community water supplies must be stable so as to not cause a violation of 35 Ill. Adm. Code 601.101(a). b) The following water quality parameters of finished water must be evaluated to ensure that water qu…

Section 604.905 Carbon Dioxide Addition a) Unless carbon dioxide addition is provided in the form of a carbonic acid and water solution under pressure, recarbonation basin design must provide: 1) a total detention time of 20 minutes; and 2) a depth that will provide a diffuser su…

Section 604.910 Phosphates Phosphate solution must be kept covered and disinfected by carrying approximately 10 mg/L free chlorine residual unless the phosphate is not able to support bacterial growth and the phosphate is being fed from the covered shipping container. Phosphate s…

Section 604.915 Split Treatment A lime softening water treatment plant can be designed using "split treatment" in which raw water is blended with lime softened water to partially stabilize the water prior to secondary clarification and filtration. Treatment plants designed to uti…