Answers to the questions we're asked most often.

Typical arrival is within 45 minutes inside our core coverage area (Hemel Hempstead, Watford, St Albans, Luton, Aylesbury, Milton Keynes). For life-or-flood emergencies we aim for 30 minutes in HP1–HP3. Ring 07404 216065 for a live ETA based on where our vans are right now.

Yes — every day of the year, including Christmas. We work in shifts so a real human always picks up. Out-of-hours work (after 8pm weekdays, weekends, bank holidays) carries a small uplift, which we'll explain on the call.

Our line is answered 24/7. If you get a queue tone you are next; average hold is under 30 seconds. If for any reason the line is unreachable, email info@oncall-plumbing.co.uk with your postcode and a callback number — we'll ring back within 10 minutes.

For a burst pipe or major leak: turn off the mains stopcock (usually under the kitchen sink). For a leaking boiler: switch off the boiler at its switched spur and shut the internal gas valve if safe. Open taps to drain the system down. If you smell gas, leave the property and ring the National Gas Emergency line on 0800 111 999 first.

Yes — a small call-out fee covers the engineer's travel and the on-site diagnostic. Once the fault is diagnosed you'll get a fixed price to fix it there and then, and you decide whether to go ahead. No work starts, and no fix-cost is charged, without your say-so.

Yes. After the on-site diagnostic the engineer talks you through what's needed and gives you a fixed price for the fix before any work begins — your call whether to proceed.

We operate 24/7 including weekends and bank holidays. An out-of-hours uplift may apply outside normal working hours — we'll explain it on the call.

Yes — every engineer we send is individually Gas Safe registered for the appliances they work on, and you can verify their registration on the Gas Safe Register.

A real human in our Hemel Hempstead dispatch office, 24 hours a day — average pick-up under 30 seconds.

Both. We install, service, and repair combi, system, and regular boilers across Worcester Bosch, Vaillant, Ideal, Baxi, Glow-worm, Viessmann, Potterton, Alpha and Ariston.

Yes. CP12 inspections are usually completed in a single visit, with the certificate emailed within 24 hours.

Usually, yes. We locate leaks with thermal imaging and acoustic listening first. About 70% of hidden leaks are accessible without major floor disturbance.

Yes. Unvented hot water systems need an annual service by a G3-certified engineer — we have qualified engineers on the team.

Core: Hemel Hempstead (HP1–HP3), Watford (WD17–WD25), St Albans (AL1–AL4), Luton (LU1–LU4), Aylesbury (HP19–HP22), Milton Keynes (MK1–MK9). Plus Berkhamsted, Tring, Harpenden, Chesham, Amersham, Rickmansworth, Dunstable, Leighton Buzzard.

Yes. Landlords, letting agents, shops, offices, pubs and small industrial sites — we work with all of them.

Yes. We provide itemised reports, photos, and moisture readings suitable for insurance claims (Aviva, AXA, Direct Line, Hiscox, and major brokers).

Boiler cover is a monthly subscription that may not cover your specific fault and routes through third-party engineers with longer waits. On Call is pay-as-you-go with vetted local Gas Safe engineers, and you only pay when we come out.

Card on completion using the card reader in the van — Visa, Mastercard and Amex. A receipt is emailed straight after.