All data in the Water Measurement Information System (WMIS) is coded to understand the quality. The below explains each quality code and broadly categorises its reliability.
| Quality | Text |
| 1 | Unedited data |
| 2 | Good quality data - minimal editing required. +/- 0mm-10mm drift correction |
| 3 | Used only by TELEM Data, must not be archived |
| 4 | Good quality data. Edited by Hyadjust. Minimal editing required +/- 0mm-10mm drift correction |
| 5 | Drawdown affecting site due to hydraulic conditions (slope/increased velocity/density); can cause diff b/w gauge board and instrument readings |
| 6 | Different rating table used when level is rising compared to falling. |
| 8 | Pool reading only - no flowing water |
| 9 | Site/bore dry |
| 10 | Data transposed from recorder chart |
| 11 | Reviewed data without field adjustment (or correction) |
| 12 | Unverified rainfall data awaiting annual rain gauge calibration |
| 13 | Accurate derived data from multiple sources (level & flow) |
| 14 | Unstable hydraulic conditions occurring due to high velocity |
| 15 | Minor editing. +/- 11mm-20mm drift correction |
| 16 | Minor editing. Edited by Hyadjust. +/- 11mm-20mm drift correction |
| 17 | Level reference set incorrectly |
| 18 | Logger removed from bore for airlifting/bore development |
| 19 | First measurement since MP change / bore refurbishment |
| 21 | Low velocity acoustic record affected by wind or gate |
| 22 | Changed conditions at site. Not representative of stream conditions |
| 26 | Daily gauge board readings |
| 30 | Good measurement. Flow Trackers and M9 should be held for 40sec at each vertical reading across the cross section |
| 31 | Good Measurement commonly used QC for gaugings. Flow Trackers/M9 should be held for 40sec at each vertical reading across the cross section |
| 32 | Fair measurement. Used where there is turbulent flow, Vegetation growth, inadequate verticles, or non uniform flow conditions |
| 33 | 3 Point measurement. Applicable to narrow sections eg. Pipes or channels |
| 34 | Bucket measurement applicable to weirs, pipe outflow etc. |
| 35 | Composite measurement. Segments taken from several gaugings |
| 36 | Measurement for sampling purposes. Rough estimate |
| 37 | Measurement estimated |
| 38 | Quality or method unknown |
| 39 | Catchment area defined (catchment rating table only)/ moving boat measurement |
| 40 | Catchment area not defined (catchment rating table only) |
| 42 | Low velocity acoustic record affected by wind or gate opening |
| 43 | Good manual GW measurement |
| 44 | GW - data from water corporations, consultants or government agencies |
| 45 | GW - data from universities or CMAs |
| 46 | GW - data from landholders |
| 47 | GW - historic data from the GMS (validation unknown) |
| 50 | Moderate editing +/- 21mm-30mm drift correction |
| 51 | Single point high velocity measurement M9 use only. Water velocity > 3m/s |
| 52 | Moderate editing. Edited by Hyadjust. +/- 21mm-30mm drift correction. |
| 65 | Other authorities supplied data. Validation not supplied |
| 76 | Interpolation between two points less than 24 hours apart, not a correlation |
| 77 | Correlation with other station, same variable only |
| 80 | Accumulated (rainfall or flow totals only) |
| 82 | Linear interpolation across gap in records. (<0.5 day) |
| 90 | Salinity interpolation (data management section use only) |
| 96 | Daily read records substituted for continuous record lost due to natural cause/vandalism |
| 99 | Sensor out of calibration (see comments) |
| 100 | Irregular data, use with caution. (+30mm drift / >15% of range of instrument) |
| 101 | Drawdown rating applied |
| 104 | Records manually estimated |
| 145 | Rating created via modelling |
| 146 | Interim rating table |
| 147 | Rating based on measurements older than 20 years |
| 148 | Theoretical rating table applied. |
| 149 | Rating extrapolated 1.5 times the maximum flow gauged. |
| 150 | Rating extrapolated above 1.5x maximum flow gauged |
| 151 | Data lost due to natural causes / vandalism (see additional quality info) |
| 152 | Contractual issues affecting data collection or site/bore access |
| 153 | Data not recorded. Probe out of water/below instrument threshold |
| 154 | Data unreliable. Acoustic sensor affected by wind |
| 155 | Data unreliable. Recording above instrument range |
| 156 | Drawdown - normal rating does not apply |
| 157 | Unreliable data (bore data) |
| 158 | Unreliable data - awaiting correction from field validation |
| 160 | Stage backed-up by downstream influence (see additional quality info) ? |
| 161 | Poor quality data from debris effecting sensor |
| 165 | Suspect or bad data supplied by other authority |
| 170 | Raw unedited data stored in archive, secondary/backup sensor (see additional quality info) ? |
| 180 | Data not recorded, equipment malfunction |
| 190 | Data unavailable station discontinued |
| 200 | Data available but not digitised |
| 235 | Poor Measurement. Inadequate verticals or observations. Incomplete M9 measurement |
| 236 | Suspect or Incomplete Measurement. Equipment suspect or gauging aborted |
| 237 | Surface velocity measurement only |
| 238 | Control leaking measurement. As noted on measurement or chart |
| 239 | Backed up flow measurement. Flow affected by backup |
| 240 | Not Coded Measurement. Not coded as per Hydsys system |
| 241 | For Melbourne Water purposes (temporary code) |
| 250 | Rating table suspended |
| 254 | Rating table exceeded |
Reviewed 14 June 2024