Black Well Water – What Is It And Is It Harmful?


Homeowners who get their water from a private well would probably be horrified if it suddenly started flowing out of the faucets tinted black. Although it looks unpalatable, there is no need to panic as it might be an easy fix. Yet action should be taken promptly to solve the problem and restore the quality of the water. 

There are various reasons to explain why your well water is black. A common cause is the oxidation of mineral deposits such as magnesium, manganese and iron. In other cases, such discoloration can be linked to the presence of highly concentrated rust, mildew, sand or clay particles, or even plumbing issues. 

In this article we will explain how to identify the cause of black water and the most adequate solutions to repair and prevent further issues. We will also discuss any possible safety risks involved.

Mineral deposits

Manganese, magnesium and iron are widely occurring minerals found in water systems. They may produce black specks in your water when in contact with oxygen while emerging from your faucets.

In small traces, these substances are not harmful to humans. In fact, they are essential for our nutrition. However, these minerals may stain plumbing fixtures, laundry and dishes, plus they give your water an unappealing look and unpleasant taste.

It can also affect your water pipes if they are made of a material that reacts to these elements. 

Rub the specks between your fingers and if it leaves a black powder then it is very likely that you have an excess of these minerals built up in your water system.

Other symptoms are an oily water surface and brown, orange or red stains on your sinks and bathtubs. A mixture of baking soda and white vinegar can be utilized to scrub the stains that manganese caused in your fixtures. 

Contact a certified laboratory to conduct a test as soon as possible.


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If the results show high levels of manganese, magnesium or iron, the solution is simple: install a water filtration system or water softener that works on these specific minerals as they come out of the faucets.

Another option is to contract a professional to treat your well to remove the minerals from the source using chlorine or other oxidizing agents. 

Sand, silt or clay particles

Private wells are prone to the leach of small amounts of sand, silt or clay into the water pumped out of the faucets.

These do not present a health risk but make water crunchy, plus they can cause damage to your well pump and water using appliances.

The possible problems leading to the presence of such sediments are:

  • The improper development of a new well
  • An increase in pumpage, either due to the installment of a larger pump or a water fixture that uses a lot of water
  • An old sandstone well with a sloughing formation
  • Screen failure due to excessive incrustation  

A quick test implies filling a glass with tap water and letting it sit to check whether the sand drops to the bottom.

In the case of a new well, sometimes letting the water run for a couple of days clears out the problem.

You might need to install a liner to seal off a sloughing formation, or a new screen if there is none or the current one is ineffective. 

Rusty pipes

Rust in your plumbing system can leach into your water and become oxidized, turning it orange, red, brown or even black.

This is a problem most commonly found when you have aging steel, iron, copper or galvanized pipelines.

Signs of corroded pipes are the irregular shape and size of the black particles, their hard texture and the fact that they stop appearing when you leave the water running.

If the black specks appear only in your hot water, then the corrosion is in the hot water heater. A plumber will be able to inspect and diagnose the condition of your pipes and water heater.

Any rusty segments should be repaired or replaced by a licensed professional.

Rust in minimal quantities is not a major health and safety issue, but a risk of lead poisoning means that you should stop drinking the water until the issue is solved.

Rust also makes your water smell and taste bad. 

Granular activated charcoal

GAC is a substance used as the filtration agent within the cartridge of many home water filter systems. Its particles are very hard and uniformly shaped like coffee grounds.

Ingesting a small amount of GAC is harmless as it is comparable to medical charcoal.

However, the presence of GAC particles in your drinking water suggests a malfunction in your filtration system, which should be fixed by replacing the cartridge following the manufacturers’ instructions. 

Mold or mildew

Damages in your plumbing system such as leaks and cracks can lead to mold and mildew building up in your pipes over time, turning your water black.

If left untreated, spores can spread quickly into your home, presenting a risk to your furniture, building foundation and most importantly, to your health.

Mold is more likely to develop if you have a private well, as well caps tend to go loose or deteriorate providing space for mold to grow.

If you suspect that mold or mildew are discoloring your water, you should call a plumber immediately.

Although there are DIY methods to prevent the growth of mold in your pipes, only a professional will be able to tackle the problem from the source and avert further issues. 

Disintegrating rubber gaskets or hoses

If your water is coming out of your faucets with oily, smudgy debris that makes it look black, then there is probably a flexible rubber fixture breaking down somewhere along your plumbing system.

If the black rubbery specks are coming out only from one faucet, then there is probably a decaying washer or gasket in that faucet head that needs replacing.

If the black water is coming out from various water sources, then the disintegrating rubber hose is probably the one connected to the water heater. This should be replaced by a professional plumber. 

Final words

In most cases, black water is an aesthetic effect with no serious consequences to your health. Yet finding black sediments is evidence that there is an irregularity at some part of your water supply.

You should have your private well tested regularly, especially when there are variations in the odor, taste or color of your water.

Prompt action to repair any issues will prevent them from escalating into more serious problems. It is always better to be safe than sorry, in particular when it comes to something so essential as the water you use regularly.

While the causes for black water mentioned above are the most common ones, there are special cases in which bacteria, fecal matter and construction material can infiltrate into your water supply and turn your water dark.

Seeking advice from a professional plumber and getting an expert to analyse the composition of your well water are strongly advisable.


Best Well Water Test Kit – QWT Water Testing Kits – $189.99

Retail Price: $228.50
You Save: $38.51
from: Quality Water Treatment Inc

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