Short answer:

Water tank contamination symptoms can include changes in water smell, taste, colour, clarity or visible sediment, while some contaminated-water exposures can cause stomach pain, diarrhoea, nausea or vomiting. Symptoms alone cannot prove that your tank is responsible. Check the source, sump, tank, pipes and taps, then test the water when the concern persists.

Key takeaways

• Changes in smell, taste, colour or clarity deserve investigation.
• Illness symptoms alone cannot identify the source of contamination.
• Contamination can enter at the source, tank or downstream plumbing.
• Water testing is more reliable than guessing from symptoms.
• Stainless steel does not purify contaminated source water.

If you are unsure whether the problem is your tank or another part of the system, message Skywell on WhatsApp with your tank capacity and water-source details. You can ask before deciding whether replacement is necessary.

What are the first signs of possible water tank contamination?

The first signs to investigate are a sudden or persistent change in water smell, taste, colour, clarity or visible sediment. These signs do not identify the contaminant, but they can tell you that the water system needs closer inspection.

Your overhead tank is only one part of the route your water takes before reaching the kitchen. A change at the tap may originate at the source, sump, tank, pipework or even one particular outlet.

A dirty-looking tank is also worth checking. Look for visible sediment, deposits, unusual material or anything entering through an opening.

The CDC states that tap-water contamination can occur at the source or while water travels through pipes to a home or building. That guidance is international rather than Kerala-specific, but the source-tracing principle applies to a household storage system. (CDC, “What Causes Tap Water Contamination,” July 31, 2024.)

There is one mistake I would avoid: blaming the overhead tank before checking where the water-quality change actually begins.

Can contaminated water cause symptoms?

Yes, contaminated water can be associated with illness, but the symptoms depend on what has entered the water and cannot by themselves identify your tank as the cause.

The CDC states that symptoms vary according to the germ or chemical involved and notes that many waterborne germs can cause stomach pain and diarrhoea. (CDC, “Water Quality and Your Health,” July 16, 2024.)

Some chemical contaminants can also cause symptoms such as nausea, vomiting, diarrhoea or stomach pain, depending on the substance and exposure. (CDC, “Chemicals That Can Contaminate Tap Water.”)

That distinction matters in a Kerala household.

If two people develop stomach problems, you cannot diagnose the tank from that fact alone. Food, person-to-person infection, source water and other environmental exposures can also be relevant.

A health concern should be discussed with a medical professional. A suspected water-quality problem should be investigated through appropriate water testing. Do not make the two questions answer each other.

What should you check before blaming the tank?

Start by tracing the water system from source to tap: source → sump → pump → overhead tank → pipes → tap. The location where the change first appears can help narrow down what needs inspection.

If the problem appears only at one tap, start there. If it appears throughout the house, move further upstream.

Kerala Water Authority states that its quality-control system tests water from supply schemes and also accepts private samples through its district laboratories. Its testing programme covers physical, chemical and bacteriological parameters. (Kerala Water Authority, “Quality Control.”)

Then inspect the sump and overhead tank.

Check the lid, inlet and overflow arrangements. Look for visible sediment or deposits. Consider whether rainwater, dust, animals, debris or another unwanted source could enter the storage system.

The CDC’s safe-storage guidance recommends storage that protects treated water from recontamination and says storage containers should be cleaned regularly. (CDC, “Safe Water Storage,” April 22, 2024.)

Seven checks worth making

1. Incoming water: Has its colour, smell or taste changed?
2. Sump: Is there visible sediment or unusual material?
3. Tank interior: Is there visible dirt, deposits or other material?
4. Lid and openings: Are they properly closed and protected?
5. Overflow and inlet: Could unwanted material enter through either opening?
6. Pipework: Could the problem be downstream of the tank?
7. Taps: Does the same change appear at multiple outlets?

That last check can be useful.

If the kitchen tap has an unusual smell but another outlet does not, the tank may not be the only suspect.

Should you test your water?

If you have a persistent concern, water testing gives you evidence that visual inspection and symptoms cannot provide.

Kerala Water Authority says private water samples can be tested at its district laboratories and publishes testing information for household water-quality samples. Its listed parameters include colour, odour, turbidity, pH, electrical conductivity, total dissolved solids, hardness, chloride, fluoride, iron, nitrate, residual chlorine, total coliforms and E. coli. (Kerala Water Authority, “Quality Control” and “Quality Testing.”)

KWA also states that samples from about 20,000 locations of various water-supply schemes are taken and analysed on average each year. That is a Kerala Water Authority monitoring figure, not a measurement of every household water source in Kerala. (Kerala Water Authority, “Quality Control.”)

Testing does not automatically mean your tank needs replacement.

If the result points to a source-water problem, the source needs attention. If it points to a plumbing issue, replacing the tank may not solve the problem. If inspection shows the tank itself is damaged or unsuitable, replacement becomes a separate decision.

For another practical reference, you can read our guide to tank maintenance in Kerala