How many litres per hour from the tap?

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How many litres per hour come out of your tap?

The question of how many litres per hour come out of a tap has two answers that you need to keep well apart: what your connection can maximally deliver, and what actually runs out of your tap.

The first figure is spelled out in black and white in your water company's tariff schedule. An ordinary home has a small-consumer connection of 1.5 cubic metres per hour, so 1,500 litres per hour. That is the capacity the connection and the water meter are designed for, and it is immediately the ceiling: you will never get more than 1,500 litres per hour out of it, no matter how many taps you open.

The second figure is a good deal lower, because a single tap never uses that capacity in full. The spout, the tap outlet and the length of pipe slow the flow down. For one fully opened kitchen tap, expect 8 to 16 litres per minute, or roughly 500 to 950 litres per hour. At PureFilter we see people badly underestimate that difference: a tap left open for ten minutes has already used 100 litres, which is almost a full day's drinking water for one person.

Litres per minute per fixture, at a glance

Because almost everyone thinks in litres per minute yet calculates in litres per hour, both are listed below. The per-fixture figures come from Vitens and Milieu Centraal; converting to litres per hour is simply times 60.

The bottom two rows are the reason this topic is not only technically interesting. A thin trickle of 16 litres per hour sounds like nothing, but according to Waterbedrijf Groningen it adds up to 140,000 litres a year. A running toilet comes to 219,000 litres a year. Anyone wondering how many litres per hour their tap gives would do well to ask that same question about their leaks.

Measure it yourself: the bucket test in three steps

Every table figure is an average. Your home has its own pressure, its own pipe length and its own spout, so the only figure that truly applies to your tap is the one you measure yourself. Milieu Centraal describes exactly this method for the shower, and it works just as well at the kitchen tap.

1. Catch it: put a measuring jug or a bucket with a scale under the tap and turn it fully open.
2. Time it: hold it for exactly 60 seconds, or fill a 10-litre bucket and clock how long that takes.
3. Convert it: litres in one minute times 60 is your flow rate per hour. If it takes 30 seconds to fill 10 litres, you're at 20 litres per minute, so 1,200 litres per hour.

Why your tap gives less than your neighbour's

Four things determine the difference, and all four can be checked.

1. The pressure on the line

Dutch drinking water companies supply with a lower bound. PWN states that water pressure is at least 2 bar. That's enough for any normal fixture, but on a high floor or at the end of a long street you will, in practice, end up lower than your neighbour on the ground floor.

2. The strainer in the spout

This is the most common cause and the cheapest fix. Vitens names a clogged strainer on the tap as the most frequently found reason for too little water pressure, and advises unscrewing the tap head and cleaning the strainer with vinegar. Five minutes of work, no cost. In areas with hard water that strainer clogs faster, and it's the same limescale you see again in your kettle.

3. A flow restrictor or aerator

Many modern taps have one built in as standard. An aerator mixes air into the stream, so less water passes through while the stream still feels just as strong. That's not a defect but a design choice, and according to Vitens it's one of the simplest ways to counter water waste at the tap.

4. What sits before the tap

A Quooker with a reservoir, a boiler, a long flexible connection hose or an old shut-off valve under the countertop: each part costs a little flow. Anyone with a boiling-water tap who wonders what that does to the cold fixture will find the explanation on our page about the Quooker water filter. And if nothing comes out at all anymore, that's a different story: read what to do when no water comes out of the tap anymore.

From litres per hour to litres per day

A flow rate of 500 to 950 litres per hour sounds enormous, until you set it next to actual household consumption. In 2021 a Dutch household used, on average, 129 litres of drinking water per person per day, reports Milieu Centraal. Well over 40 percent of that goes to bath and shower, 24 percent to the toilet and 13 percent to laundry. The Dutch government wants that consumption back down to 100 litres per person per day by 2035.

Put differently: your entire daily consumption runs through one open tap in about a quarter of an hour. An average 8-minute shower costs about 70 litres according to Vitens, and a bath about 140 litres according to Milieu Centraal. Turning the tap off while brushing your teeth saves 22 litres per person per day, which is more than most people drink in a day. If you want to know how much water you need per day to drink, that's a fraction of that total, and precisely the litres where quality matters most.

What does an hour with the tap open cost?

Now that you have a flow rate, the sum is short. Waterbedrijf Groningen arrives, in 2026, at €2.82 per 1,000 litres including taxes, built up from €1.16 for supply, the Tap Water Tax of €0.437 per cubic metre and 9 percent VAT, plus the standing charge you already pay anyway.

That last row is the most important one in the table: a tap that doesn't close properly costs you more per year than two complete water filters. The full breakdown of the water bill, including the difference per water company, is in our piece on what a cubic metre of water costs. At this price per litre, the real cost story of bottled water also stands out: a litre of spring water costs €0.40 to €1.00, so 140 to 350 times as much as the same volume from your tap.

What does a water filter do to the flow?

This is the question behind the question. Anyone considering an under-sink filter wants to know whether their tap will still fill a pan in thirty seconds afterwards. The answer depends entirely on the type of filter, and that difference is bigger than people expect.

An inline filter sits in the pipe. The water simply runs through it under the existing line pressure, from the cold water supply via the filter housing to your tap. There's no storage tank in between and no pump. The PureFilter Mineral+ works this way: you connect it in 5 to 10 minutes with a single water pump pliers onto the cold water line, and the water comes out of your existing tap. What that looks like in practice is laid out step by step in our guide to installing a water filter yourself.

A reverse osmosis system works differently. With reverse osmosis, the water is forced through a membrane that only lets through a limited amount per hour, which means a storage tank is needed and rinse water is discharged. The speed at your fixture is then determined by the tank, not by your pipe. Anyone who wants to understand the technology before choosing can read how reverse osmosis works. And anyone who first wants to see which types of water filters exist and what they can handle can then compare more precisely.

There is one more practical point related to flow: a filter that becomes saturated noticeably slows down. That is exactly the signal to replace it, and the reason we quote a fixed lifespan per household size instead of a vague interval. If your tap runs slower while your filter is still young, check the spout first, and also keep an eye on the temperature of your tap water: cold water that stays lukewarm for too long points to a different problem than a spent filter.

PureFilter next to the alternatives

At PureFilter we see that the speed argument often tips the balance. Anyone who used to work with a jug is not just choosing better filtering, but above all the disappearance of the waiting. If you want to see what else suits a kitchen like yours, take a look at a filter that sits on the line and compare the variants by filter package.

What to pay attention to

• Measure before and after: do the bucket test first with your current tap, and write down the figure. Then you'll know later whether a change really comes from the filter or from something else.
• Connection size: the PureFilter Mineral+ comes standard with a 3/8 connection. If you're unsure whether that fits your tap, just call before ordering on 085 888 1501.
• Cold water only: a drinking water filter belongs on the cold water line. If you have a Quooker, place the filter before the system, on the cold water supply.
• Hard water: in areas with a lot of limescale, spouts and strainers clog up faster. You'll notice that first in your flow rate and only afterwards in your kettle.
• Filter lifespan depends on your household: one cartridge lasts up to 12 months for 1 to 3 people and up to 6 months for 4 to 6 people. So never mix the two up.
• No need for scaremongering: Dutch tap water meets the standards. A filter is there for the traces the standard allows, and for taste.

Frequently asked questions

Conclusion

The question of how many litres per hour come out of a tap is answered with three figures. Your house connection can deliver 1,500 litres per hour, one open tap gets you 500 to 950 litres per hour of that, and you measure your own figure in one minute with a measuring jug. The conversion is simple: litres per minute times 60.

What makes those figures valuable is what you do with them. They show that a thin trickle costs 140,000 litres a year, that your daily consumption of 129 litres runs through a single tap in a quarter of an hour, and that tap water at about 0.28 cents per litre is hundreds of times cheaper than bottled water. And they make clear why filter technology matters: an inline filter keeps the pace of your pipe, a reverse osmosis system with a storage tank does not.

The PureFilter Mineral+ costs €149.00 including the first filter, is NSF certified to 42, 53, 61 and 372, filters more than 100 contaminants and adds calcium, magnesium and potassium back as a final step via Swedish Mineral Rock™. A replacement filter costs €65.00 and lasts up to 12 months for 1 to 3 people, about €0.18 per day. With 40 days of free returns and a 5-year warranty, you can measure for yourself whether you notice a difference in your flow, and whether you notice a difference in your glass. Anyone who wants to buy a water filter right away can choose the filter package that fits their household size.