Thanks so much Lesley. Do you know what brand you have?

If only our plumbers had done what they were supposed to do, we'd almost certainly plump for water softener but sadly that doesn't appear to be the case.

Most water softeners are a retro installation so I can't see any reason why a softener can't be installed with the only compromise being the location and many modern softeners are more compact than the older softeners. I wouldn't let not being left any plans for the plumbing deter you (but i'd still get them as they're your property) as a competant plumber should be able to figure out how your hot and cold pipework is run, its not rocket science.

Get a quote from a few plumbers and then send the bill to your builders and plumber with a threat of a CCJ and see if that spurs them on to send you all the plans (inc plumbing and wiring) for your property as they've breached the agreed contract you had with them.

Never heard of these conditioners, but you know that water softeners work and they actually make a difference. Looking on line at the differences did highlight that 'conditioned water won’t permanently stay conditioned. It will quite quickly return to an unconditioned state. So, if it is used in conjunction with stored water, i.e. a tank in the loft or a hot water tank, scale will still develop' taken from https://www.sjwatersofteners.co.uk/whats-the-difference-between-a-water-softener-water-conditioner/ 

You might find this interesting (american site so UK water is possibly better quality?) https://waterfiltercast.com/water-conditioner-vs-water-softener/

Had a water softener for the past 10 years - it moved house with us. Tapworks brand. Needs to be fitted at the water source so it can do the whole system but leave an unsoftened spur for drinking. Ours is fitted under the kitchen sink (retro) and does take up a whole cupboard. Although we did look at creating an insulated box on the outside to house it. Just about to get a big kitchen renovation where the water pipe will need to be re-sited and we’ve requested it be housed in the utility room. Plumber recommended we keep the same appliance as it works.

Thanks so much Lisa. We'd hoped to have water softener too. Being forced to look at conditioners as both builder & project manager completely overlooked plumbing for this so it would be a bit of a major overhaul. The conditioner looks considerably easier to fit to the system but the reviews are so so mixed.

We are going for an Aquabion type solution (not them exactly, but a similar product). I read things about how the sodium in water softeners is bad for aquatic life and the environment and decided that wasn't the way I wanted to go. We haven't yet finished our project, so I'm yet to say if the alternative works, though!

​@lesleycurrant what is the brand of your water softener? Is the maintenance expensive?

Why not get upto date and buy the latest and best for less with no ongoing costs and upto 20 years lifespan ?

See: X.com/nanodewater

@Dereck Swordsward

Bit concerning that you're using softened water in your kettle, the water that comes from a water softener isn't drinkable due to the salts, your kitchen tap and outside tap should be direct from the mains and not via a water softener.