NR 809.04(3)(3) “Coagulation” means a process using coagulant chemicals and mixing by which colloidal and suspended materials are destabilized and agglomerated into flocs.

NR 809.04(4)(4) “Combined distribution system” means an interconnected distribution system consisting of the distribution systems of wholesale systems and of the consecutive systems that receive finished water.

NR 809.04(5)(5) “Community water system” or “CWS” means a public water system which serves at least 15 service connections used by year-round residents or regularly serves at least 25 year-round residents. Any public water system serving 7 or more homes, 10 or more mobile homes, 10 or more apartment units, or 10 or more condominium units is a community water system unless information is available to indicate that 25 year-round residents will not be served.

NR 809.04(6)(6) “Compliance cycle” means the 9-year calendar year cycle during which public water systems monitor. Each compliance cycle consists of 3, 3 year compliance periods. The first compliance cycle begins January 1, 1993 and ends December 31, 2001; the second begins January 1, 2002 and ends December 31, 2010; the third begins January 1, 2011 and ends December 31, 2019.

NR 809.04(7)(7) “Compliance period” means a 3-year calendar year period within a compliance cycle. Each compliance cycle has 3, 3-year compliance periods. Within the first compliance cycle, the first compliance period runs from January 1, 1993 to December 31, 1995; the second from January 1, 1996 to December 31, 1998; the third from January 1, 1999 to December 31, 2001.

NR 809.04(8)(8) “Comprehensive performance evaluation” or “CPE” means a thorough review and analysis of a treatment plant’s performance-based capabilities and associated administrative, operation and maintenance practices. It is conducted to identify factors that may be adversely impacting a plant’s capability to achieve compliance and emphasizes approaches that can be implemented without significant capital improvements. For purposes of compliance with this chapter, the comprehensive performance evaluation consists of at least the following components: Assessment of plant performance; evaluation of major unit processes; identification and prioritization of performance limiting factors; assessment of the applicability of comprehensive technical assistance; and preparation of a CPE report.

NR 809.04(9)(9) “Confirmed presence” means the presence of coliform bacteria in a water sample confirmed by a total coliform-positive repeat sample.

NR 809.04(10)(10) “Confluent growth” means a continuous bacterial growth covering the entire filtration area of a membrane filter, or a portion thereof, in which bacterial colonies are not discrete.

NR 809.04(11)(11) “Consecutive System” means a public water system that receives some or all of its finished water from one or more wholesale systems through a master metering system. This public water system may also be known as a wholesale purchaser or wholesale customer. Delivery may be through a direct connection or through the distribution system of one or more consecutive systems.

NR 809.04(12)(12) “Conventional filtration treatment” means a series of processes including coagulation, flocculation, sedimentation, and filtration resulting in substantial particulate removal.

NR 809.04(13)(13) “Contaminant” means any physical, chemical, biological, or radiological substance or matter in water.

NR 809.04(14)(14) “Corrosion inhibitor” means a substance capable of reducing the corrosivity of water toward metal plumbing materials, especially lead and copper, by forming a protective film on the interior surface of those materials.

NR 809.04(15)(15) “CT” or “CTcalc” is the product of the residual disinfectant concentration (C) in mg/l determined before or at the first customer, and the corresponding disinfectant contact time (T) in minutes, i.e., “C” x “T”. If a public water system applies disinfectants at more than one point prior to the first customer, it shall determine the CT of each disinfectant sequence before or at the first customer, to determine the total percent inactivation or “total inactivation ratio.” The inactivation ratio for a single disinfectant sequence is:

where “CTtable” is the CT value required for the target organism and the target level of inactivation as contained in ss. NR 810.47 to 810.61. The sum of the inactivation ratios, or total inactivation ratio for a series of disinfection sequences is:

and is calculated by adding together the inactivation ratio for each disinfection sequence. In determining the total inactivation ratio, the water supplier determines the residual disinfectant concentration of each sequence and corresponding contact time before any subsequent disinfection application points. A total inactivation ratio equal to or greater than 1.0 is assumed to provide the target level of disinfection of the target organism.

NR 809.04(16)(16) “Department” means the department of natural resources.

NR 809.04(17)(17) “Diatomaceous earth filtration” means a process resulting in substantial particulate removal in which:

NR 809.04(17)(b)(b) While the water is filtered by passing through the cake on the septum, additional filter media known as body feed is continuously added to the feed water to maintain the permeability of the filter cake.

NR 809.04(18)(18) “Direct filtration” means a series of processes including coagulation and filtration, but excluding sedimentation, resulting in substantial particulate removal.

NR 809.04(19)(19) “Disinfectant contact time” (“T” in CT calculations) means the time in minutes that it takes for water to move from the point of disinfectant application or the previous point of disinfectant residual measurement to a point before or at the point where residual disinfectant concentration (“C”) is measured. Where only one “C” is measured, “T” is the time in minutes that it takes for water to move from the point of disinfectant application to a point before or where residual disinfectant concentration (“C”) is measured. Where more than one “C” is measured, “T” is:

NR 809.04(19)(a)(a) For the first measurement of “C”, the time in minutes that it takes for water to move from the first or only point of disinfectant application to a point before or at the point where the first “C” is measured; and

NR 809.04(19)(b)(b) For subsequent measurements of “C”, the time in minutes that it takes for water to move from the previous “C” measurement point to the “C” measurement point for which the particular “T” is being calculated. Disinfectant contact time in pipelines is calculated based on “plug flow” by dividing the internal volume of the pipe by the maximum hourly flow rate through the pipe. Disinfectant contact time within mixing basins and storage reservoirs shall be determined by tracer studies or other department approved equivalent demonstration.

NR 809.04(20)(20) “Disinfection” means a process which inactivates pathogenic organisms in water by chemical oxidants or equivalent agents.

NR 809.04(21)(21) “Disinfection profile” means a summary of daily Giardia lamblia inactivation through the treatment plant. The procedure for developing a disinfection profile is contained in s. NR 810.32.

NR 809.04(22)(22) “Distribution system” means all pipes or conduits by which water is delivered to consumers except piping and fixtures inside buildings served, water services and private water mains as defined in ch. SPS 381.

NR 809.04(23)(23) “Domestic or other non-distribution system plumbing problem” means a coliform contamination problem in a public water system with more than one service connection that is limited to the specific service connection from which the coliform-positive sample was taken.