Low Water Pressure

Having low water pressure is annoying as it slows the cycle times on many appliances including washing machines, dishwashers, reticulation and hot water units.

There are many factors which can cause low pressure, below we have listed a few:

  • Incoming supply pressure from the mains
  • Incorrect Pipe sizing
  • Restriction in the piping or valves
  • A burst section of pipe allowing pressure to drop
  • Head and distance of supply and outlets
  • Hot water systems
  • Flow restrictors

It can also be combinations of the above.

1. Incoming supply pressure

We can carry out a pressure and volume test at the incoming water meter which will usually tell us what the available pressure and volume to the property is.

  • Water Care is obligated to deliver a min of 20 litre/min volume at the meter
  • Water meters at device 150kpa (15m head)

Some parts of Auckland will typically deliver 350kpa – 45 litres per min.

Often we get complaints of insufficient water pressure to retic and second storey bathrooms.

How we can help – If you have low water pressure from the mains?

If we find you are getting above 150kpa at the meter, Water Care will not be obligated to help you.

KD Plumbing can increase the pressure by increasing the delivery pressures. To do this we can create a water storage tank and pump system that will guarantee a pre-set pressure to the system.

Pressure and volume work in conjunction with each other i.e.; water pressure from 150 to 450kpa will increase water delivered at the end of the pump by 100%.

Generally the cost of this type of system ranges from $5000 to $7000 and depends on factors such as size and structure of the storage tank, if it’s above or below ground.

The minimum size of the water tank should be 1000 litres and this also depends on factors such as the amount of fixture units on the system.

If you would like us to design a solution for you, please contact KD Plumbing now.

2. Pipe sizing

In some older houses the pipe work is undersized, compared to the modern dwellings. Some homes have all of the hot pipe work run in 15mm copper which is 1/2”.

The longer the pipe run and the more bends used, the pressure decreases at the point of delivery. In new builds, correctly sized hot lines will solve any shortfall in pressures.

It can be difficult to retrofit large pipework into old houses and is sometimes not a viable option. Call us today for a consultation.

What is the solution – to lack of volume?

  • Upgrade pipe sizes
  • Upgrade the pressure (via the pumping method)

If you would like KD Plumbing to help solve this problem, please contact us today.

3. Restrictions

Water volume can be reduced by restrictions in the pipeline, kinked pipework, faulty valves, blockages in the pipe and long distances causing resistance on the water delivery.

Generally, the pressure is high when you first turn the tap on and then drops off. Pressure is constant and the drop is caused by a greater volume of water on one side of the obstruction.

The water then spreads out in the pipework and the pressure at delivery is decreased.

Having multiple bends in valves and long runs of pipe also cause the same problems.

What is the solution?

KD Plumbing can locate the problems areas and remove the restrictions. Most of the time this involves replacing of sections of pipework to bypass the fault.

If you would like this problem solved for you, please contact us now.

4. Bursts

Water leaking from our systems will also lower the pressure, for example if you are losing 3 litre/min into the ground the pressure will drop.

What’s the solution?

  • Carry out a pressure test on the system
  • Locate the leak and carry out a repair

If you would like KD Plumbing to help with this problem, please get in touch now.

5. Heights

As the height of water pressure increases the pressure decreases.

For every 2m of height you will lose 20kpa. For example if you have 150 kPa coming in and you try to raise it by 10m you will have lost 100 kPa in pressure.

What’s the solution?

A pump system (as seen above)

Install a storage tank on top of the roof, in the attic or ceiling space which will store the water and allow gravity to deliver the water. This solution will require correct pipe sizing and the higher the tank the greater the pressure will be.

If you would like us to help with this, please contact KD Plumbing now.

6. Hot water systems

Some hot water systems restrict the flow of ‘hot’ water, the reason they do this to allow more time for the water to stay in contact with the source of heat.

What is the solution?

In this situation a pump will not be much help.

One solution is to install a mains pressure hot water unit such as a Rheem or Rinnai.

If you would like us to help with this, please contact KD Plumbing now.