4 Eye-Opening Facts About Hot Water Pressure

Is the shower pressure at your HDB or high rise condo low?
Why does your rain shower not work as advertised?
Can I install a booster pump to increase my water pressure?

If you find yourself asking these questions, read on!

Here are four eye-opening facts about water pressure in Singapore.

#1 Where You Live Matters

High rise apartments

Homes 25m below sea level get direct water supply from PUB. Homes above this mark get indirect water supply from the water tank.

Water pressure varies in these two separate sections. Common feedback:
  • water pressure is higher on low floors
  • water pressure is lower on high floors
Private housing

Houses with levels 25m below sea level get direct water supply from PUB. Levels above the mark get water from a tank at the roof.

Water pressure is around 12 to 18 lit/min, direct supply from PUB.

#2 The Heater Affects Water Pressure

Modern luxuries demand higher water pressure

In the past, most Singaporeans were content with low pressure heaters. Today, luxuries like rain showers are all the rage. These run on high water pressure. Try to take away someone’s rain shower option and you’ll see how upset they get!

If you check into a 5-star hotel today and they’re using low pressure heaters.. Your bath tub would take an hour to fill. It’s likely you’ll check out right away and maybe write a complaint.

What worked 20 years ago won’t work today as the standards have gone up. That’s why knowing what pressure each heater delivers is so important.

Instant heaters: low pressure

Instant or tankless water heaters have an in-built flow restrictor. This helps to slow down water flow rate and gives it time to heat up.

The hot water flow rate of instant heaters are 4 lit/min.


  • electric instant heaters
  • gas heaters
  • multipoint heaters
Storage heaters: high pressure

Heaters with a tank maintain the max pressure.

If cold water goes into the tank at 15 lit/min, the hot water output is 15 lit/min. The limiting factor is the flow rate of the shower head.


  • electric storage heaters
  • solar heaters
  • heat pump heaters
Can I use 1 heater for 2 bathrooms?

Storage heaters can be shared, but not instant heaters. The hot water pressure will be too low. A instant heater produces 4 lit/min, which is good for one bathroom.

Storage heaters can supply 2 to 3 bathrooms. The water pressure drop is about 20%, because they use mixers. In a mixer, hot water is mixed with cold water. The two inputs of water create higher water pressure.

#3 The Shower Head Will Affect Pressure

Different shower heads will give you varying results. It is good to understand what type of water pressure you have at home before selecting a shower. Below is a brief guide on the flow rates for each type of showerhead.

From here, you can gauge which showers you can use. The most common shower head in HDB and condos is the 10 lit/min rain shower. Landed homes have higher water pressure. They may use fancier shower jets or waterfall shower spouts.

Instant water heater: What type of shower head to use?

Every instant heater comes with a shower head set in the box. Use this. These special shower heads have smaller hole sizes. This makes the water pressure coming from your shower head feel stronger.

A shower head tip

Still feel like you’re not getting the right pressure from your shower? A simple fix: change your shower head to one with a lower max flow rate.

Many European brands have high-flow shower heads. These cater to the high end market. Paired with low-water pressure, these can make the water pressure feel weaker.

How to tell flow rate of a tap or shower?
In Singapore, all taps have a WELS label. The flow rate is on the label.
The more ticks there are, the lower the flow rate. The lower the flow rate, the more water you save.
Sometimes, you can get the best of both worlds. An efficient shower head can create higher pressure while saving money.

#4 Pressure Pumps are illegal

Every one wants higher water pressure but this isn’t always good. Pressure that is too high (5 bar and above) damages your pipework. It also decreases the lifespan of taps. Most homes do quite well within 2 to 3 bars.

In cases where water pressure is lower than average, don’t install a pressure pump on your own. Unauthorised pressure devices are illegal and may not solve the problem.

Instead, contact the Town Council or MCST for a solution. They have a full understanding of your piping and can address issues at the source.

Other related articles:

Higher water pressure is better? Not always true.

High water pressure can create some unwanted, high pitched sounds from your water heater and even put unnecessary pressure on your pipes!! Read more on how to fix that.

Instant vs. storage water heater

Using a storage will not affect your water pressure, but using an instant heater will see pressure drops of at least 50%. Find out why.

Gas vs. electric water heaters

Gas heaters are also pressure reducing systems. If showers in both bathrooms are running at the same time, users will feel a flow rate drop.


Do heat pumps have a pressure pump?

No. Heat pumps are a type of storage heater. They get their name by ‘pumping’ free air heat into the water heater. This does not increase the pressure of the water heater.

Instant electric heaters give you 4 lit/min. Booster pump instant heaters come with a small booster pump, which is legal. They have a slightly higher flow rate, 5 lit/min.

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Amanda is an education specialist at AOS Bath. She enjoys building a trusted network by sharing knowledge. Making difficult concepts simple and engaging is rewarding, on both ends.