The City of Cape Town has advised residents to keep an emergency supply of 2 to 5 litres of water as it starts further pressure reduction which may interrupt supply to some high lying areas.

''Residents are advised that supply interruptions are now more likely due to intensified water pressure reduction measures,'' said the city’s mayoral committee member for informal settlements water, and waste services; and energy, Xanthea Limberg.

''As such, residents should keep an emergency water supply on hand for drinking and basic hygiene. Furthermore, despite hoaxes to the contrary, municipal water remains safe to drink," she said on Thursday.

Limberg added that although water may taste earthy, it is safe to drink.

On Wednesday, the City of Cape Town's council approved Level 4 water restrictions that started on Thursday.

The water pressure reduction is the city's way of stretching the little water left to supply the city, with no rain in sight as the disastrous drought continues.

''As we have never had to lower pressure to this level, reaching this equilibrium will require an element of trial and error," said Limberg.

Multi-storey buildings that do not use pumps and overhead tanks as required by the City’s building regulations are likely to have supply problems.

Residents must also make sure their body corporates and managing agents are geared up for the severe restrictions.

Anybody who has supply interruptions should report it to 0860 103 089 so that the City can make the necessary adjustments.

Limberg advises storing between 2 to 5 litres of water for drinking and basic hygiene.

The city wants people to limit their daily water use to no more than 100 litres a day.

To stay within this limit, residents should not shower for more than two minutes per person, toilets are to be flushed only when absolutely necessary and with grey water, and all internal plumbing and plumbing fixtures must be checked for leaks.

Level 4 water restrictions include the following:

-    No irrigation/watering with municipal drinking water is allowed;

-    Private swimming pools may not be topped up or filled with municipal drinking water, even if they have a cover;

-    No washing of vehicles and boats with municipal water is allowed (commercial car washes may apply for an exemption which will only be granted if wash water is recycled or waterless products are used);

-    Water features may not use municipal drinking water;

-    No hosing down of paved surfaces with municipal drinking water is allowed;

-    Use of portable play pools is prohibited.