1. (a) The components of an alternative collection system must be sized based on existing flow data from a similar system and service area, if such data is available.
2. (b) If flow data from a similar service area with a conventional wastewater collection system is used, the report must include the expected effects of inflow and infiltration on the peak flow of the system.
3. (c) Design and construction of an alternative wastewater collection system must minimize excess flows from inflow and infiltration.
4. (d) Roof, street, or other type of drain that permit entrance of storm water into a wastewater collection system is prohibited.
5. (e) In the absence of existing data, the sizing of on-site components in an alternative wastewater collection system must use Figure: 30 TAC §217.32(a)(3), Table B.1 of this title (relating to Organic Loadings and Flows), in conjunction with the following equation:
   Attached Graphic
   

6. (f) Design of the off-site components must be based on the maximum flow rate expected, calculated using the following equation:
   Attached Graphic
   

   1. (1) An equivalent dwelling unit (EDU) is assumed to have an occupancy of 3.5 people. For EDU population greater than 3.5, the following equation must be used:
      Attached Graphic
      
   2. (2) The safety factor, "B", may be adjusted if higher wastewater flows are anticipated. A discharge from commercial or institutional dischargers must be measured directly or calculated under this subsection.

Source Note:The provisions of this §217.92 adopted to be effective August 28, 2008, 33 TexReg 6843.