PDFWAC 173-173-170
What alternative water measuring devices and methods can I use?
Any responsible party may use an alternative water measuring device or method that differs from those described in this chapter, if:
(1) The method is approved in writing in advance by the department; and
(2) The device(s) and installation are certified by a registered professional engineer or other qualified person acceptable to the department to:
(a) Measure all flow diverted or withdrawn in accordance with the pipeflow or open channel accuracy requirements in WAC 173-173-100(2) and 173-173-130(1);
(b) Measure the appropriate volumes and flow rates in WAC 173-173-060;
(c) Be installed and operated according to the manufacturer's and/or designer's instructions, and other such conditions as the department may find necessary.