Key values
| Topic | Value | EPHS (item) |
|---|---|---|
| Bunkering and production | Continuously halogenated to at least 2.0 mg/L free halogen at the time of bunkering or production, with an automatic device. pH not above 7.8 | 5.2.1.1.1 (03, critical) |
| Monitoring | Once the target is reached: free halogen and pH at least hourly during bunkering, at least every 4 hours during production | 5.2.1.2.2 (08) |
| Production at sea only | Reverse osmosis, distillation or other production for the potable system only while the vessel is making way. Not in polluted areas, harbors or at anchor | 5.1.2.1.1 (03, critical) |
| Distribution system | Free halogen of at least 0.2 mg/L and at most 5.0 mg/L throughout the distribution system | 5.4.1.2.1 (04, critical) |
| Disinfection after possible contamination | At least 50 mg/L free halogen throughout the affected area for 4 hours, or another procedure accepted by VSP. In an emergency: at least 200 mg/L for 1 hour | 5.3.5.3 (07, critical) |
| Flushing after disinfection | Flush or dechlorinate to 5.0 mg/L or less. Record the measured value | 5.3.5.4 (08) |
| Line marking | Potable lines striped or painted blue/green/blue (ISO 14726) or blue only | 5.3.3.1.1 (08) |
| E. coli sampling | At least four samples per month from the forward, aft, upper and lower decks. Change the sites monthly. Follow up each positive result | 5.6.1.1.1 (06) |
| Cross-connection control | A listing of every cross-connection with its backflow prevention method or device, matched to component and location, air gaps included | 5.7.1.1.4 (08) |
Values in short form. The binding text is the CDC VSP 2025 Environmental Public Health Standards, section 5.
What VSP cites in potable water
In 871 public VSP inspection reports from 2022 to 2026, item 08 (hoses, caps, fittings, sample valves, system construction) was cited in 73% of the reports. About six in ten of these deficiencies concern backflow devices, cross-connections or air gaps. The most cited single requirement here is keeping backflow prevention devices in good repair (EPHS 5.7.2.1.1). All findings.
Check it on board
In Sightyard USPH, the daily check "Potable water: halogen and pH monitoring" and the area pages for the bunker station, tanks and distribution system list every potable water requirement with how to check it and the CDC text. Open usph.sightyard.com, the library is free.