Water Pressure in Irish Homes: How to Check Yours Before You Buy a Tap or Shower
Sep 08, 2026
Water Pressure in Irish Homes: How to Check Yours Before You Buy a Tap or Shower
More returned taps come back for this reason than any other. Not because the tap was faulty, and not because it was badly fitted — but because the house could never have driven it in the first place. A tap rated from 1 bar fitted to a gravity system running at 0.3 bar will dribble no matter who installs it.
The frustrating part is that the check takes about five minutes and costs nothing. You need to know two things: which type of system you have, and roughly how much pressure reaches the outlet you care about. Everything else follows from those.
This guide covers both, with the numbers worked out for the kind of houses actually built in Ireland — including the attic tank and hot press cylinder setup that is still in most homes built before the 2000s, and the reason a mixer tap misbehaves in the kitchen of one.
The quick answer
Go and look in your hot press and your attic. A cold water tank in the attic feeding a copper cylinder in the hot press means you are on a gravity system, and you should be buying taps rated to work from 0.5 bar or lower. Anything else and you almost certainly have the pressure for whatever you fancy.
That single check settles most of it. The rest of this page tells you how much pressure you actually have, why the shower upstairs is weaker than the tap downstairs, and what to do about it if the answer is disappointing.
Check pressure carefully if:
- The house was built before roughly 2000 and has not been re-plumbed
- There is a tank in the attic and a cylinder in the hot press
- The shower upstairs has always been weak
- You are buying a pull-out kitchen tap, a boiling tap, or a thermostatic shower
You can relax if:
- There is a combi boiler on the wall and no cylinder anywhere
- The cylinder is a sealed pressurised one with an expansion vessel beside it
- Your cold taps run hard and fast on every floor
- The house is a newer build or was fully re-plumbed
Step one: which system do you have?
There are three arrangements in Irish houses, and you can tell them apart in under a minute without touching anything.
| System | How to spot it | Hot water pressure |
|---|---|---|
|
Gravity fed Vented, open system |
Cold water tank in the attic, copper cylinder in the hot press with an immersion switch. Very common in Irish houses built before the 2000s. | 0.1–0.6 bar, depending entirely on how far the outlet sits below the tank |
|
Combi boiler No stored hot water |
A boiler on the wall, no cylinder in the hot press, no tank in the attic. Hot water arrives whenever you open a tap. | Mains pressure, usually 2–4 bar — but the flow is limited, which matters (see below) |
|
Pressurised cylinder Unvented, sealed |
A cylinder in the hot press but no attic tank, with a red or white expansion vessel and a cluster of valves plumbed beside it. | Mains pressure, usually 2–4 bar, with good flow from several outlets at once |
One thing that trips people up. Even on a gravity system, the cold tap at the kitchen sink is nearly always plumbed straight off the mains, because that is the drinking water supply. So the kitchen cold runs hard while everything else in the house runs soft. Do not judge the whole house by that one tap — it is the least representative outlet you own.
Step two: the height rule that explains everything
On a gravity system, your water pressure is not set by the water company or the boiler. It is set by how far the outlet sits below the water level in the attic tank, and nothing else. The rule is simple enough to do in your head:
Which is why the shower upstairs has always been the weakest thing in the house. It is the highest outlet, so it is the closest to the tank, so it has the least height working for it. In a standard two-storey house the shower head might be under two metres below the tank — about 0.2 bar, which is not enough to drive most thermostatic valves properly.
Measure it yourself if you want the real number for your house. From the water level in the attic tank, straight down to the outlet: every metre is worth about 0.1 bar. A tank sitting on the attic floor rather than raised on blocks costs you a surprising amount at the shower head.
Step three: measure what actually comes out
Pressure is what pushes the water; flow rate is what you feel. For choosing a tap, flow is the more useful of the two and you can measure it with a bucket and your phone.
- Pick the right outlet. Test the one you are buying for. The kitchen cold tap tells you about the mains; the bathroom hot tap tells you about the cylinder. They can be wildly different in the same house.
- Use a container you know the size of. A five litre bucket is ideal. A two litre bottle works.
- Open the tap fully and time the fill. Just that outlet, nothing else running in the house.
- Do the sum. Litres divided by seconds, multiplied by 60. A five litre bucket filled in 25 seconds is 5 ÷ 25 × 60 = 12 litres per minute.
- Repeat on hot. If hot is much slower than cold, that is your answer about the cylinder, and it is the thing that will bother you daily.
| What you measured | Where that puts you | What it will run |
|---|---|---|
| Under 6 l/min | Very low — almost certainly gravity, and not much of it | Basin taps rated from 0.5 bar. A shower will need a pump. |
| 6–9 l/min | Low but workable | Low pressure basin and kitchen mixers. A gravity shower will feel soft. |
| 9–12 l/min | Moderate — typical of a combi | Most mixers and a thermostatic shower valve, one outlet at a time. |
| 12–15 l/min | Good | Nearly anything, including pull-out sprays and bath fillers that fill quickly. |
| Over 15 l/min | Strong — mains or a pressurised cylinder | Everything, boiling water taps and multi-outlet showers included. |
If you want the actual bar figure, a screw-on pressure gauge costs about the price of a takeaway and screws onto an outside tap or a washing machine valve. Worth it if you are planning a full bathroom rather than swapping one tap — and worth taking a reading in the evening as well as the morning, because mains pressure drops when the whole estate is showering.
Why your kitchen mixer runs hot then cold
This one catches people out constantly, and it is not a fault in the tap.
In a gravity-fed house, the hot water comes from the cylinder, which is fed by the attic tank — so it arrives at maybe 0.3 or 0.6 bar. But the cold at the kitchen sink comes straight off the mains at 2 to 4 bar, because that is the drinking supply. Put both into one mixer tap and the cold side wins comfortably. You get lukewarm water when you asked for hot, the temperature wanders as other taps in the house open and close, and in some cases the cold pushes back up the hot side entirely.
Plumbers call this an unbalanced supply, and the tap is only the messenger. The fixes, in order of cost:
- Buy a tap rated for unbalanced or low pressure supply. The cheapest answer, and often good enough. Twin lever taps handle imbalance better than single lever ones, because you set each side yourself instead of hunting for a blend point that keeps moving. The Deva Walton and Newton both run from 0.3 bar, which is about as low as a kitchen tap goes.
- Fit a pressure reducing valve on the cold feed to bring it closer to the hot. A plumber’s job, but a small one.
- Balance the system properly — run the kitchen cold from the tank as well, or pump the hot. Bigger work.
Upstairs is usually less affected, because in most gravity houses the bathroom cold comes off the attic tank too, so hot and cold arrive at the same pressure and mixers behave themselves.
What each type of fitting actually needs
Manufacturers state a minimum on every product page — ours included — but here is the general shape of it, so you know what you are looking for before you start comparing.
| Fitting | Typical minimum | Works on gravity? |
|---|---|---|
| Mono basin mixer, low pressure rated | 0.3–0.5 bar | Yes |
| Waterfall basin mixer | 0.5 bar | Usually — check the rating |
| Kitchen single lever mixer | 0.5 bar | Yes, if rated from 0.5 |
| Kitchen twin lever mixer | 0.3 bar | Yes — the most forgiving option |
| Kitchen tap with pull-out spray | 1 bar | No — the spray needs pressure to work |
| Bath filler | 0.5–1 bar | Yes, but slow to fill |
| Bath shower mixer | 0.5 bar | Yes if there is real height above it |
| Thermostatic shower valve | 0.5–1 bar | Only if specified for low pressure |
| Electric shower | Around 1 bar and 8 l/min | Runs off the cold mains, not the cylinder |
| Instant boiling water tap | 1 bar | No |
That last row is worth dwelling on if a boiling tap is on your list — they need a bar minimum and will not work off a hot press cylinder. There is more on that in our boiling water tap running costs and installation guide, which covers the socket and cupboard requirements as well.
If the pressure is low, what are your options?
Cheapest first, because the cheapest one solves it for most people.
- Buy fittings rated for what you have. Genuinely the sensible answer nine times out of ten. A twin lever mixer rated from 0.3 bar will feel perfectly normal on a gravity system, where a 1 bar tap would disappoint you every day. It costs nothing extra — you just have to read the specification before you order.
- Raise the attic tank. Sitting it on a properly built platform half a metre higher adds about 0.05 bar everywhere. Small, but free-ish, and it helps the shower most because the shower needs it most.
- Fit a shower or whole-house pump. A single impeller pump boosts one supply, a twin impeller boosts hot and cold together — which is what you want for a mixer shower. If your shower sits at or above the tank level you need a negative head pump specifically, so say that when you are buying.
- Convert to a pressurised cylinder. Replaces the cylinder and removes the attic tank, giving mains pressure at every outlet. The best result and the biggest job, and it only works if the incoming mains has enough pressure and flow to begin with — so measure first.
One thing you cannot simply do: bolt a booster pump onto the incoming mains. Boosting straight off the public supply risks pushing water back into the mains, so a booster set is normally required to draw from a break tank with an air gap rather than from the mains directly. That turns a simple pump into a proper installation. Talk to a plumber and to Uisce Éireann before you buy anything on the strength of a product listing.
Five mistakes worth avoiding
- Testing the kitchen cold tap and assuming the house is fine. It is on the mains and nothing else is. Test the outlet you are actually buying for.
- Assuming a combi means unlimited hot water. A combi gives you mains pressure, but its hot flow is capped by the boiler — often around 10 to 12 litres a minute. Run the shower and the kitchen tap together and both suffer. This is a flow problem, and no tap will fix it.
- Blaming a new tap. Before you conclude the tap is wrong, unscrew the aerator at the spout and look. In hard water areas a scaled aerator halves the flow within a couple of years, and it costs nothing to clean or replace.
- Forgetting the stopcock. More than one “low pressure” complaint has been solved by opening a stopcock that was left half shut after previous work. Check it before you spend money.
- Buying on looks and checking pressure afterwards. The order that saves money is: work out what you have, filter to what suits it, then choose the one you like best from what is left.
Taps and showers that suit low pressure
These are rated to work from 0.5 bar or lower — the twin lever kitchen taps go down to 0.3 — which covers most gravity fed Irish houses. Every product page states its own minimum, so check it against the number you measured.
Newton Chrome Kitchen Tap — Twin Lever
- Runs from 0.3 bar — the lowest we stock
- Twin levers cope well with an unbalanced supply
- Swan neck, 360° swivel, 12 year Deva guarantee
Kinlin Brushed Brass Waterfall Basin Mixer
- Rated 0.5 to 3 bar, high and low pressure
- Open waterfall spout, squared body
- Also in polished chrome and matt black
Victorian Tudor Bath Shower Mixer
- Suits gravity, pumped and combi systems
- Traditional round body, 12 year guarantee
- Bath filler and shower from one fitting
Newton Thermostatic Shower Valve
- Specified for low and high pressure systems
- TMV2 thermostatic — holds temperature steady
- Concealed single outlet, chrome
If you measured 1 bar or more, the whole range is open to you — including pull-out spray kitchen taps and boiling water taps, both of which want a bar minimum. Browse the full kitchen taps, bathroom taps and showers and valves, and check the stated minimum on each product page before ordering.
Not sure after all that? Send us the flow figure you measured and which floor the outlet is on, and we will tell you straight whether something will work in your house before you buy it.
Frequently Asked Questions
How do I know if I have a gravity fed or a combi system?
Look in the attic and the hot press. A cold water tank in the attic feeding a copper cylinder in the hot press means gravity fed. A boiler on the wall with no cylinder and no tank means a combi. A cylinder with no attic tank, with an expansion vessel and valves beside it, means a pressurised or unvented system.
What water pressure do I need for a mixer tap?
Most standard mixer taps want at least 1 bar. Taps specified for low pressure work from 0.3 to 0.5 bar and are what you need on a gravity system. The minimum is stated on every product page — it is the first figure to check, before finish or style.
How do I check my water pressure at home?
For flow rate, fill a container of known volume from the tap and time it: litres divided by seconds, multiplied by 60, gives litres per minute. For actual pressure in bar, screw an inexpensive pressure gauge onto an outside tap or washing machine valve. Test the specific outlet you are buying for, not just the kitchen cold tap.
Why is my upstairs shower so weak?
On a gravity system, pressure comes only from the height between the attic tank and the outlet. A first floor shower head might sit less than two metres below the tank, which is roughly 0.2 bar — the weakest point in the house. Raising the tank helps a little; a pump or a pressurised cylinder helps a lot.
What is negative head, and do I need a special pump?
Negative head means the outlet sits at or above the water level in the tank, so gravity gives you nothing at all. A standard pump will not start reliably in that situation — you need a pump specified for negative head, which senses the outlet opening rather than waiting for flow.
Does a combi boiler give high water pressure?
It gives mains pressure, usually 2 to 4 bar, which is plenty. What it limits is flow: the boiler can only heat so much water a minute, often around 10 to 12 litres. That is why a combi feels strong at one outlet and weak when two are running at once.
Can I fit a booster pump to my mains water supply?
Not as a simple bolt-on. Boosting directly from the public mains risks pushing water back into the supply, so a booster set normally has to draw from a break tank with an air gap instead. Check with a plumber and with Uisce Éireann before buying a pump on the strength of a product listing.
Why does my kitchen mixer tap run hot then cold?
Because the supplies are unbalanced. In a gravity house the kitchen cold comes off the mains at 2 to 4 bar while the hot comes from the cylinder at well under 1 bar, so the cold side dominates the mixer. A twin lever tap rated for low pressure, or a pressure reducing valve on the cold feed, is the usual fix.
What pressure does an electric shower need?
An electric shower runs off the cold mains rather than your hot water cylinder, and typically wants around 1 bar and at least 8 litres a minute. That makes it a common answer in gravity fed houses where the cylinder cannot drive a mixer shower properly.
Will a new tap fix low water pressure?
No, but the right tap will make low pressure far less noticeable. A tap rated from 0.3 bar is designed to deliver a sensible flow at that pressure. Fitting a 1 bar tap to a 0.3 bar supply will disappoint you regardless of how good the tap is.
What pressure do boiling water taps need?
Typically 1 bar minimum, running best between 1 and 3 bar. They will not work properly on a gravity fed cylinder, which rules them out for a lot of older Irish houses unless the system is changed first.
Is it worth converting to a pressurised cylinder?
It gives the best result — mains pressure at every outlet, and no attic tank. It is also the biggest job, and it only works if your incoming mains has enough pressure and flow to feed it. Measure the mains first, then get a quote, then compare that against simply buying fittings rated for what you already have.
