Stormwater gravity drains may be combined with clearwater drains prior to discharging to the storm building drain only if approved by the department.

• A. They may be combined, but only with approval by the department.
• B. They may be combined at any time.
• C. They may not be combined prior to discharging to the storm building drain, unless approved.
• D. They must always be kept separate.

Answer: (C)

The test is about keeping stormwater and clearwater drains separate unless there’s explicit authorization to mix them. Stormwater and clearwater are treated as two streams that discharge toward the storm building drain, and mixing them can create capacity, backflow, or contamination issues, so any joining before discharge is tightly controlled. Therefore, the correct idea is that you generally cannot combine these drains prior to discharging to the storm building drain unless the department approves. This matches the conditional allowance—only with official approval may the two drains be combined. Choices that imply mixing could occur freely or that separation is mandatory without any approved exception aren’t aligned with how the rule is applied.