Why is My Tap Water Cloudy?

Published 10.12.2023

According to Water UK, the United Kingdom has some of the world’s most stringent water treatment processes. Passing 99.97% of tests, our water is filtrated and undergoes various pre-treatments to eliminate harmful natural and synthetic chemicals. 

With such a high level of quality control, it’s no wonder UK homeowners expect clear, clean water to flow from their taps on every occasion. 

But that’s not always the case. Sometimes, tap water may take on a cloudy appearance, and this phenomenon, while common, often raises concerns about the safety of our drinking water. 

Thanks to rigorous testing and treatment processes, cloudy water is usually not a sign of a dangerous problem. However, the specific causes can range from harmless natural occurrences to indications of underlying issues in our plumbing systems.

Why is my tap water cloudy? 

There might be several reasons your tap water is cloudy, including: 

Sediment particulates in the water supply

Sediments such as sand, silt, or rust can sometimes enter the water supply, particularly through older or disturbed pipes. 

Events like bursts in the water main or construction work can stir up these particles and give your water a cloudy appearance. 

Trapped air bubbles 

Trapped air bubbles can form in tap water because of pressure changes. Your water pressure may change following maintenance work or due to fluctuations in the local water supply system. 

When water under pressure reaches a tap, and the pressure is released, air bubbles form, giving the water a cloudy appearance. It’s a temporary and harmless effect; the water will clear as the bubbles rise and escape.

You live in a hard water area 

In parts of the UK with hard water, the high mineral content, particularly calcium and magnesium, can be a factor behind cloudy tap water. 

These minerals, naturally present in the water, can accumulate in domestic water systems, leading to limescale build-up. This build-up can sometimes cause the water to appear cloudy, especially when agitated or heated. 

While this does not pose a health risk, it can affect the taste and appearance of the water. Dealing with hard water cloudiness might involve installing water softeners, filters, or calcium treatment units to reduce mineral content.

Types of coloured water 

Generally, cloudy tap water is safe to drink. It may take on a misty, hazy quality indicative of trapped air bubbles, particulate matter or living in a hard water area. 

However, sometimes your water may change from clear or cloudy to blue, black, yellow or orange. But what do these colours mean? 

Blue or green 

This discolouration can be caused by copper leaching inside household pipes or storage cylinders. 

Factors contributing to this include high-pressure boiler settings or unusual pH levels. Blue water requires immediate attention and testing to verify its safety. 

Black/brown 

The presence of black or brown water is often a result of iron or manganese sediments from the water supply network, particularly from older pipes. 

These sediments can cause the water to appear dark when disturbed, such as during maintenance or pipe bursts​. 

Slimy bits

This could indicate bacterial growth or the presence of other organic matter in the water supply. It’s often a sign of a need for system maintenance or cleaning. However, it could also indicate that parts of your filtering material are in water. 

Yellow (straw-coloured) 

Yellow or straw-coloured water can be caused by a variety of factors, including decaying organic matter or the presence of certain minerals. It often occurs in areas with high iron levels or regions with specific geological conditions.

Grey/cloudy

As discussed, this is typically due to air bubbles in the water. It’s a common and harmless condition resulting from changes in water pressure and clears up as the air bubbles escape. 

Brown/orange 

Usually caused by high levels of iron or manganese in the water, brown or orange water can occur after disturbances in the water supply network, such as repairs or changes in flow, dislodge these minerals and mix them into the water supply. 

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All UK home and business owners will experience cloudy water at one time or another. 

It’s a harmless phenomenon often caused by underlying issues in the plumbing system or external sources, like an increased presence of natural minerals. 

However, if you’re looking for additional peace of mind, options like bottled water coolers, drinking fountains, and hot water dispensers can be a wise choice. With our products, you’ll have access to a consistent supply of clean, quality water just a few steps away.