# Water in the AdBlue tank | what to do now > Water in the AdBlue tank: Likely recoverable. Water in the AdBlue tank dilutes the urea below the 32.5% that ISO 22241 specifies, so… - URL: https://adblueinfuel.co.uk/water-in-the-adblue-tank/ - Focus: water in the adblue tank - Updated: 2026-09-22 - Phone: 01295 380724 (From just £89 call-out fee) - Publisher: AdBlue in Fuel — a service by Forecourt Assist — Forecourt Assist is a trading name of Fuel Fixer Ltd, company no 08520551, registered at Fairway House, Portland Road, East Grinstead, RH19 4ET, a company of Fuel Fixer International. --- ## Water in the AdBlue tank Short answerWater in the AdBlue tank dilutes the urea below the 32.5% that ISO 22241 specifies, so the system under-doses, NOx conversion fails and a fault follows. It is usually recoverable by drain and flush — call 01295 380724. AdBlue is 32.5% urea in demineralised water for a reason: that is the eutectic concentration, the one that freezes lowest and doses predictably. Dilute it and you have not made a weaker but working fluid — you have made a fluid the dosing map is wrong for. The engine management doses on the assumption of 32.5%, under-delivers ammonia, fails its NOx conversion check and logs a fault. Tap water adds minerals on top; demineralised does not, but the concentration problem remains. Call 01295 380724 From just £89 call-out fee ## Water in the AdBlue tank — the severity verdict **Key facts** | Severity | Likely recoverable Usually resolved by a drain and flush, with a fluid-quality check afterwards. | What went where | Water in the AdBlue tank | Direction | Into the AdBlue tank | Typical cost | £170–£360 typical total, from a £89 call-out | Time on site | About 60 minutes | Call-out | From just £89 call-out fee | Helpline | 01295 380724, 24 hours £89 is the call-out. An AdBlue tank drain and flush is quoted on the phone before a technician travels. If the SCR system needs component replacement — dosing injector, pump, tank or catalyst — that is separate, and you will be told before any work starts. If this is a job we cannot fix at the roadside, we will tell you that on the phone rather than after we arrive. ## What to do right now - Note whether it was tap water or demineralised — it changes the flush. - Avoid unnecessary running. - Do not attempt to correct the concentration by adding AdBlue. - Call 01295 380724. ## What a technician actually does Drain, flush, refill with fresh AUS 32, read and clear the stored NOx and dosing codes, and a short dosing verification. ## Why this is not the same job as the other direction This is contamination of the SCR dosing circuit — tank, metering pump, heated lines, dosing injector and potentially the catalyst. It is not the fuel system, and it is not the cheaper job. Anyone quoting a flat drain price for this has not looked at the system. ## Common questions ### Surely AdBlue is mostly water anyway? It is 67.5% demineralised water — at one specific concentration. The dosing strategy is calibrated to that concentration. Dilution is not a milder version of the same fluid. ### Can I top it back up with concentrated urea? No, and concentrated urea is not what is sold to you. The fix is to remove the wrong fluid, not to chase a ratio. ### Will it damage anything? Dilution alone usually does not damage components. The cost is the drain, the flush and the fault clearing — plus any miles driven with NOx conversion out of spec. ## What customers say 4.8 out of 5 from 2,190 Trustpilot reviews. What reviewers mention most is that the technician stayed calm and professional with a driver who was embarrassed and stressed, and that somebody arrived when they said they would. The most common criticism is price. People do not expect a wrong-fluid job to cost what it costs, and that is a fair complaint to publish rather than bury. The answer is the From just £89 call-out fee, a quote given on the phone before a technician travels, and being told when a job cannot be done at the roadside rather than after somebody has arrived and charged for the visit. ### Related AdBlue problems Diesel in the AdBlue tankPetrol in the AdBlue tankScreen wash in the AdBlue tankTap water in the AdBlue tankOil in the AdBlue tankCoolant in the AdBlue tankWrong AdBlue — non ISO 22241 fluidContaminated AdBlueExpired AdBlueOverfilled AdBlue tank ### Start from a symptom instead AdBlue warning light is onA countdown to no restart is showingThe engine will not restartPower loss or limp modeWhite crystal deposits on or under the vehicleThe AdBlue gauge reads wrong ### By vehicle class CarsVansPickupsHGVsBuses and coachesMotorhomesAgricultural and plant ### Where we cover Water in the AdBlue tank in Belgrave LeicesterWater in the AdBlue tank in CaernarfonWater in the AdBlue tank in Cranleigh ## Who you are dealing with AdBlue in Fuel is a service by Forecourt Assist. Forecourt Assist is a trading name of Fuel Fixer Ltd, company no 08520551, registered at Fairway House, Portland Road, East Grinstead, RH19 4ET, a company of Fuel Fixer International. Fuel Fixer International is owned by Stockbridge Capital Holdings. Reference: Urea (Wikipedia). ## Across the Fuel Fixer network Fuel Fixer IrelandMisfuel DoctorDiesel in PetrolFuel Doctor FleetThese are sister brands of the same company, not unrelated sites. Forecourt Assist keeps the canonical list at forecourtassist.co.uk/network rather than duplicating it here.