| Chemical | Works on | Destroys | Safe for septic? | |----------|----------|----------|------------------| | Caustic soda (NaOH) | Grease | Rubber seals | No | | Sulfuric acid | Paper, rags | Cast iron, human tissue | Absolutely not | | Enzyme cleaner | Organic waste | None (slow) | Yes |
| Company | Specialism | Response time | |---------|------------|---------------| | Harpenden Drain Care | Root cutting, CCTV | 2 hours | | 24/7 Drain Rescue (Herts) | Emergency jetting | 45 minutes | | Thames Water (utility) | Shared/lateral drains | 4 hours (emergency) | | Rothamsted Property Services | Relining, no-dig repair | 24 hours | drain unblocking harpenden
01582 461 461 (Herts County Council out-of-hours drainage line – redirects to Thames Water). This guide is informational. Always consult a qualified drainage engineer for diagnosis. Last updated: 2025. | Chemical | Works on | Destroys | Safe for septic