Who must comply
SB 555 requires California urban retail water suppliers to submit a validated water loss audit to the Department of Water Resources (DWR) every year. The audit quantifies apparent and real losses so agencies can act on them.
Validation means the audit follows the AWWA M36 methodology and the underlying data has been verified for accuracy.
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What AWWA M36 validation means
The audit breaks water loss into apparent losses (meter inaccuracies, unauthorized consumption, data errors) and real losses (leaks, breaks, overflows).
Validation flags data gaps, like missing meter accuracy data or unknown customer counts, and requires the agency to document assumptions.
The data you need
System input volume (source + purchased water).
Billed consumption by customer class.
Meter accuracy and testing records.
Estimated real loss components from your distribution data.
Common gaps we fix
Incomplete service connection counts, which skew customer meter accuracy estimates.
Unreported system input, especially unmeasured sources.
Missing meter testing documentation that drives apparent loss.
After the audit
A validated audit gives you a defensible baseline, corrective actions, and the documentation to support capital planning and funding applications. We provide the full audit with DWR submittal support.