How Long Should a Plumbing Job Take?

How long should a plumbing job take?

A diagnostic visit takes one to two hours. A known component replacement takes one to three hours. An unvented cylinder swapped like for like takes a full working day, occasionally two. A combi boiler replaced in the same position takes a day, and moving it or changing the system type takes two to three. A leak you can see takes an hour or two. A leak you cannot see is open ended until it has been traced.

Those are working ranges, not promises, because almost every plumbing job splits into two clocks. The first is finding out what is wrong, which is skilled and unpredictable. The second is putting it right, which is mechanical and fairly predictable once the first clock has stopped. A single number quoted for both averages two things that behave nothing alike.

How long common plumbing jobs actually take

Small repairs sit between thirty minutes and three hours. Replacement work sits between half a day and three days. The figures below are on site working time for an engineer who arrives with the right part, in a property where the isolation works and the pipework is where it should be. Every one of them can double when it does not.

What the short jobs have in common is that the component is reachable and there is a working valve close by. When either condition fails, the job stops being about the component and becomes a job about access and isolation, which is where the hours actually go. You are rarely paying for the repair. You are paying for reaching it and for being able to turn the water off.

• Tap cartridge or washer replacement: thirty to sixty minutes
• Toilet fill valve or flush valve: forty five to ninety minutes
• Immersion heater element: one to two hours, longer when scale has locked it into the boss
• Pressure relief or expansion relief valve on an unvented cylinder: one to two hours
• Thermostatic shower valve or bar mixer: two to four hours, more when built into a tiled wall
• Annual service on an unvented cylinder: one hour to ninety minutes
• Visible leak on accessible copper: one to two hours
• Hidden leak, trace and access included: half a day upwards
• Unvented cylinder replaced like for like: one full day, two where access is tight
• Combi boiler replaced in the same position on the same flue: one day
• Boiler relocated, or a system converted from stored to instantaneous: two to three days

These are engineer hours, not elapsed hours. Two engineers on site for one day is two engineer days on the invoice. Ask how many are attending before you compare two quotes.

How long should a diagnosis take before anyone knows what is wrong?

An engineer should have a working diagnosis on a hot water fault inside the first hour and a firm one inside two. That is not optimism. The system only has a handful of ways to fail, and a competent sequence eliminates most of them quickly. If nobody can tell you what is wrong after two hours, ask what has been ruled out, because the answer shows whether there is a method underneath the time.

A sensible sequence starts by establishing what kind of system it is, because stored and instantaneous fail differently. On a stored system the engineer checks whether the cylinder is hot at the top, whether the immersion is live at the spur and at the element, whether the boiler fires on a hot water call, whether the motorised valve is opening rather than buzzing, and whether the tundish is running. On a combi it is whether the appliance fires on hot water demand and what the diverter is doing.

Each of those checks is minutes. What stretches a diagnosis honestly is an intermittent fault that will not appear on demand, or unlabelled pipework that has to be traced first. What stretches it dishonestly is fitting parts in sequence to see what happens, which bills as diagnosis but is really shopping.

A fair question at the one hour mark: what have you ruled out, and what is the next thing you will test? An engineer with a method answers in a sentence. An engineer without one changes the subject to how old the system is.

How long does a hot water cylinder replacement take?

A like for like unvented cylinder replacement is a full working day for one engineer in a normal cupboard, and two days where the unit will not come out without dismantling something. Anybody quoting three hours has either not seen the cupboard or is not intending to commission it properly. A component level unvented cylinder repair is a different job entirely and is normally finished inside a morning, which is why establishing which of the two you actually need comes before any estimate of time.

The day breaks down like this. Draining takes longer than people expect, because a large cylinder does not empty quickly through a drain cock and it has to be empty before it moves. Disconnecting is an hour or so across the flow and return, the cold feed, the expansion arrangement, the discharge pipework and the wiring. Getting the old unit out and the new one in either takes twenty minutes or half the day, depending entirely on doorways. Then the new pipework, the refill, the leak check under pressure and the commissioning record.

What legitimately makes a job take twice as long

Access and isolation are the two honest reasons a job overruns, and in London both fail often. A seized stopcock, a valve that turns but will not seal, or a cupboard boarded in since the last engineer visited will each add hours to work that should have been quick, and none of that is anyone padding a bill.

The housing stock does specific things. Victorian conversions have pipework chased into walls and run under boarding, so reaching one joint can mean opening plaster, and a leak traced in one flat is sometimes opened up in the flat below. Purpose built blocks put thermal stores such as a Pulsacoil in a riser cupboard sized exactly for the unit, so the door casing comes off before the unit does. New builds run heating pipework in liquid screed, which is cut and made good rather than lifted. That is also why leak detection and repair is timed as two separate stages, because the finding and the fixing have almost nothing in common in terms of duration.

Hard water across the London supply area is the quiet one. Scale locks immersion elements into their bosses, welds valve spindles solid and leaves sediment that has to come out before anything can be assessed. Thirty minutes of work in a soft water area is two hours here, and the engineer cannot tell which it is until the cover is off.

• Isolation that fails, so the supply is shut off further back or the system drained
• Buried or chased pipework in period conversions, where the access is most of the job
• Riser cupboards where the unit cannot be removed until something is dismantled
• Liquid screed over underfloor pipework, which is cut rather than lifted
• A part that has to be fetched, which is usually an hour of the day gone
• Communal shut offs needing agreement from a managing agent

How to sanity check an hourly bill

Compare the billed hours against the window the engineer was in your property, then ask what happened in each hour. Two things account for nearly every gap: travel and parts collection charged as labour, and a minimum charge or rounding rule nobody mentioned. Neither is unusual, and both should have been stated before the visit.

When the hours look high, ask for the sequence rather than opening with an accusation. What was tested, in what order, what was found, what was replaced. A real job produces an answer with a detail you could not have invented, like a valve that turned but would not seal. A bill that cannot produce a sequence is the one to push on.

• What time the engineer arrived at the property and what time they left
• Whether travel between jobs sat inside the rate or was charged separately
• The minimum charge, how part hours were rounded, and whether a merchant run was billed as labour
• Whether a return visit to fit an ordered part was charged as a new attendance

When a long job is a warning sign rather than a hard job

A job is running long for the wrong reasons when parts are being changed before anything has been measured. Diagnosis by replacement is the clearest tell in this trade. If an engineer fits a component, tests, then fits another, you are paying labour and parts for a process of elimination that a meter and a sequence of checks would have finished in an hour.

The second tell is the repeat visit for the same symptom. A third visit for the same complaint means the fault was never identified, only disturbed, and the question then is not how long it will take but what they now believe is wrong and what evidence supports it. The third is parts fetched one at a time. One merchant run in a day is normal. Three is a job that was never scoped.

The uncomfortable half is that some jobs which look padded are simply hard, and you cannot see the difference from the kitchen. A stopcock that shears when turned, or a screed floor over a weeping joint, produces a day that looks absurd on an invoice and was unavoidable. The separator is communication. An engineer who tells you at the moment the job changes is being straight. One who tells you at the end is asking you to take it on trust.

What to agree before the clock starts

Settle the timing expectation before attendance, in the same message where you settle the charging basis. You are asking for an estimate you can both refer back to, not a guarantee, and asking tends to produce a more careful answer than a vague booking does. Keep the job in that one thread, because if the estimate was two hours and the bill is six, the thread is what makes the conversation about facts rather than memory.

• How long this job is expected to take, as a range, given what you have described
• What would make it take longer, named specifically rather than in general terms
• The point at which the engineer stops, calls you, and you decide whether to continue
• Whether a firm price for the repair follows once the fault is identified
• Whether travel, parts collection and a return visit sit inside the time or are charged on
• Who confirms extra work in writing if the scope grows

One message covering the expected range, the stop point and the rule for extra work is the only record that exists if the invoice surprises you.