Picture two quotes on the kitchen table for the same job: replace the bath, the taps and the waste, keep the tiles, keep the layout. One is a good deal lower than the other. The obvious conclusion is that the higher one is trying it on. It might be. But before you decide, it is worth reading both again, because most of the time the gap is explained by what each plumber has decided the job is.
Day rate against fixed price
The lower quote says 'two days at our day rate, plus materials'. The higher one says 'fixed price for the job as described'. Those are two different promises. The day rate quote is a best guess at the time; if the old bath waste falls apart, the floor underneath is soft, or the hot supply turns out to be in the wrong place, day three goes on the bill. The fixed price has all of that risk priced in, and it is the plumber, not you, who absorbs the extra day if it comes. Neither is dishonest. One is cheaper on paper and dearer if something goes wrong; the other costs more up front and does not move.
Access, and what the plumber saw
One of the two came to look. The other quoted from your photographs. The one who looked noticed that the bath panel is tiled in, that the waste runs under a floor that was screeded over, and that the isolation valves under the basin have not turned in a decade. That is an extra half day and a new set of valves, and it is in the higher quote. The photo quote assumed a bath panel that lifts off and valves that work. When it arrives on site and they do not, that is where 'unforeseen extras' come from.
Parts: whose, and what quality
'Materials' hides a lot. One quote priced a bath waste and overflow at the merchant's basic line; the other priced a decent brass one because the plumber has been back too many times to replace the cheap kind. One priced flexible tails; the other priced hard copper because the cupboard allows it and it lasts longer. Neither told you, because neither thought you would care. Ask for the materials to be listed with brands or at least a grade. If you supplied the bath and taps yourself, check whether both quotes assume that, because one may still have included them.
Making good
This is the biggest silent difference. Taking a bath out damages the tiles at the edge, the silicone has to be redone, the floor at the bath end may need a patch, and the panel may not go back. The higher quote includes 'make good and re-silicone'. The lower one stops when the water runs and leaves the rest to you or a tiler. Whether that is a problem depends on your tiles, your patience and whether you have a tiler. It is a real difference in scope, not in honesty.
Reading quotes so they compare
With all that untangled, the two quotes might be closer than they looked, or the lower one might turn out to be the better deal for a straightforward room. The way to know is to send both plumbers the same written description and ask each for the same things: fixed price or day rate, what is included in materials, whether making good is in, what would count as an extra and how it would be priced. Some will not want to put that in writing. That is information too.
With 3,554 plumbers listed on this site, there is no shortage of people to ask. Browse the firms near you and pick two or three who do bathroom work, or write the job up once and request quotes on the same description. Then read the exclusions before you read the total.
