From the journal
Mains fed vs bottle fed water coolers: which is right for your office?
Updated · 7 min read
If you are weighing up a water cooler for the office, the first question is almost always the same: should it be plumbed in, or should it run on bottled water? Both options are mature, both are widely used, and there is a clear right answer for most workplaces. Below is the practical comparison we walk customers through before quoting.
The short version
For most offices with mains plumbing already in the kitchen, a mains-fed system is the better long-term choice. It is usually cheaper to run, removes the bottled-water logistics and replaces a steady stream of single-use plastic bottles. Bottle-fed coolers remain the right answer for sites where mains plumbing is impractical or the lease will not allow alterations.
| Mains fed | Bottle fed | |
|---|---|---|
| Running cost | Rental, filters and service only | Rental plus every bottle delivered |
| Needs | Cold-water supply, power, waste route | Power socket and floor space |
| Storage | None | Spare full and empty bottles |
| Hygiene | Scheduled sanitisation and filter change | Scheduled sanitisation plus clean bottle swaps |
| Best for | Most offices with a kitchen or tea point | Listed buildings, short leases, shops, salons, temporary sites |
What each one actually is
A mains-fed water cooler connects to your existing cold-water supply, runs the water through a point-of-use filter and then chills or heats it as required. The water is unlimited, the filter is changed on a schedule, and the unit itself is either freestanding or under-counter.
A bottle-fed water cooler takes its supply from a sealed bottle of spring water (typically 19 litres) which sits on top of (or beside) the cooler. When the bottle runs low, the supplier swaps it for a full one on a regular delivery route. The water is chilled by the cooler itself; no plumbing is involved.
Running cost
Mains-fed wins on cost-per-litre at almost any volume. Once the unit is installed, the only ongoing cost is the filter change and the scheduled service. Bottle-fed costs scale linearly with the number of bottles consumed, which means the busier the office, the wider the gap gets.
For a busy office getting through bottles every day, the difference in running cost between the two formats tends to grow over time. We can run the numbers for your specific volume during a site survey.
For a longer-term view of cost and sustainability, see our five-year cost and sustainability comparison, and for what drives the price of each format, our office water cooler cost guide.
Sustainability
A 19-litre bottle is reusable many times, but the bottles still need to be manufactured, washed, transported, swapped and eventually retired. A mains-fed tap removes the transport and the bottle-washing entirely. For a busy office, the carbon and plastic footprint reductions are meaningful, and they are often a key reason businesses switch.
If your business has a sustainability report to file, mains-fed makes the numbers look noticeably better. See our piece on reducing single-use plastic in the workplace for more.
Installation footprint
Bottle-fed coolers are plug-and-play. They need a power socket and floor space. If you can find a corner near the reception or in the kitchen, there is very little installation work involved.
Mains-fed needs access to your cold water supply, a nearby power socket and a way to route the waste line back into the drain. For most offices the under-counter space next to the kitchen sink is the obvious spot. The installation itself is usually straightforward, but it requires that the plumbing is workable, and your quote sets out the installation timing. Older listed buildings, period conversions and some short-term lets can be more constrained.
Reliability
Both formats are highly reliable when serviced properly. Mains-fed has slightly fewer moving parts because there is no bottle change to get wrong. Bottle-fed depends on the supplier sticking to the delivery schedule, which is why we plan routes carefully rather than running on-call.
Hygiene and sanitisation
Both formats store water in a chilled reservoir, so both fall under your workplace water hygiene duties and both need a scheduled sanitisation visit from the supplier, typically every six months, with records kept. Mains-fed point-of-use units generally carry a lower Legionella risk than bottle units because the water is not standing for long. Bottle-fed coolers also depend on clean handling at every bottle swap. Our Legionella and workplace water hygiene guide covers what to keep on file.
When bottle-fed is still the right answer
A handful of situations where we will recommend bottle-fed, with scheduled bottled water delivery:
- Listed buildings or leases that do not allow plumbing alterations
- Shop floors, building sites and temporary premises
- Salons and reception areas where mains plumbing is nowhere near
- Pop-up offices and serviced workspaces where you cannot fit the unit
- Some heritage hospitality interiors where the cooler is the right look
The hybrid answer
For larger offices it is not uncommon to install a mains-fed tap in the main kitchen and a bottle-fed cooler in a meeting-room area or reception. Each serves its purpose, both come from the same supplier, both go on the same monthly invoice.
How we recommend deciding
The simplest path is to start with the kitchen and the team size. If the kitchen has an accessible mains supply and the team is more than around ten people, a mains-fed system will almost always be the right pick. For everything else, it is worth a quick site survey before committing.
Team size also drives how big the unit should be and how many you need; our sizing guidance for office water coolers gives a starting point by headcount.
Common questions
Frequently asked
Which is cheaper to run, mains fed or bottle fed?
Usually mains fed, and the difference grows as consumption rises. Once installed, the only ongoing costs are the rental, filter changes and servicing. Bottle-fed costs rise with every bottle delivered, so the gap widens as the team grows.
Does a mains fed water cooler need a plumber?
It needs access to a cold-water supply, a nearby power socket and a route for the waste line, usually the under-sink space in the kitchen. The supplier normally handles the connection as part of installation, and the quote should set out what the work involves and when it will happen.
Does water from a mains fed cooler taste as good as bottled?
With a modern multi-stage filter, yes. UK mains water is tightly regulated, and a carbon filter removes the chlorine taste most people notice. Taste problems usually come from an overdue filter change rather than the format.
Do bottle fed water coolers need cleaning?
Yes. Both formats should be sanitised on a schedule by the supplier, typically every six months, with records kept. Bottle-fed coolers also depend on clean bottle handling at every swap.
Can we have both in the same building?
Yes. A common setup is a mains fed unit in the main kitchen and a bottle fed cooler in reception or a room without plumbing, both on one contract and one invoice.
We supply both
Get a recommendation for your building
We install and service mains fed and bottle fed coolers, so we have no reason to push one over the other. Tell us about the plumbing, the team and the lease, and we will recommend the right format with a fixed monthly quote.