By Jay Water Advisory

You pump your borehole every morning. The water comes up clear. It has no smell. It tastes fine. So it must be safe — right?

Not necessarily. And that assumption is one of the most common and most costly mistakes Nigerian households make about their water supply.

The majority of Nigerians, urban, peri-urban, and rural, depend on groundwater from boreholes and hand-dug wells as their primary water source. Yet most of those households have never had their water tested. Not once.

Why Clear Water Is Not the Same as Safe Water

Water that looks, smells, and tastes perfectly normal can still carry bacteria, heavy metals, nitrates, and chemical contaminants at levels that cause serious illness. Total coliforms exceeding the WHO standard were found in borehole water samples in Iwo, even when the physical and chemical parameters were within the WHO range. Borehole and well water across Nigeria can contain parameters outside safe ranges and the only way to know whether yours does is to test it.

What Water Quality Testing Actually Looks For

Water quality is assessed across three broad categories. Understanding them helps you know what kind of testing your situation calls for.

Physical parameters are the ones your senses can partially detect, but only partially. They include colour, turbidity (cloudiness), temperature, and odour. High levels of turbidity indicate the presence of suspended particles that may be harboring microorganisms. Colour that deviates from clear suggests the presence iron, manganese, or organic matter in the water. These can be assessed with basic field instruments or simple observation, but laboratory confirmation is always more reliable.

Chemical parameters are entirely invisible and require laboratory analysis. The key ones to test in Nigerian boreholes and wells include:

pH — measures acidity or alkalinity. Safe drinking water sits between 6.5 and 8.5 on the pH scale. Water outside this range can corrode pipes, affect taste, and indicate contamination.

Total Dissolved Solids (TDS) — measures the total concentration of dissolved substances in the water. High TDS can indicate mineral contamination, industrial pollution, or intrusion from sewage. The Nigerian Standard for Drinking Water Quality (NSDWQ) sets the acceptable limit at 500 mg/L.

Nitrates — enter groundwater primarily from sewage, pit latrines, and agricultural fertiliser. High nitrate levels are particularly dangerous for infants, causing a condition known as blue baby syndrome. The WHO limit is 50 mg/L. Given that most Nigerian boreholes are sited less than 30 metres from soakaway pits, nitrate contamination is a genuine and frequent risk.

Iron and Manganese — naturally occurring in many Nigerian basement aquifers. At elevated levels they stain laundry and plumbing, affect taste, and in high concentrations pose health risks. Research in Yola-Jimeta metropolis found iron values within WHO guidelines across most boreholes tested — but this varies significantly by location.

Heavy metals — lead, cadmium, chromium, and others enter groundwater from industrial activity, old pipes, and leachate from dumpsites. Even trace levels of heavy metals carry significant health risks including neurological damage and organ toxicity. These cannot be seen, smelled, or tasted — laboratory testing is the only way to detect them.

Microbiological parameters are perhaps the most urgently important for household health. The standard indicator organisms are total coliform bacteria and E. coli, which signal direct faecal contamination. The WHO standard and Nigeria’s NSDWQ are unambiguous, zero coliforms per 100ml of drinking water. Any detectable coliform presence means the water is unsafe to drink without treatment.

Microplastics — Beyond the conventional parameters above, emerging pollutants such as microplastics have been found in borehole water in different parts of Nigeria. Identification techniques such as Raman spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR) are used to analyse water samples to determine the quantity of microplastics or nanoplastics present in water.

Why Boreholes Are Not All Equal

One of the most important misunderstandings about groundwater safety in Nigeria is the assumption that a borehole, any borehole, is safe simply by virtue of being underground. Depth, construction quality, casing integrity, and distance from contamination sources determine safety far more than the mere existence of a borehole.

A properly constructed, deep mechanised borehole with an intact cement-grouted casing, a sealed wellhead, and a submersible pump located at least 30 metres from any sanitation facility or waste site offers meaningful protection. A shallow hand-dug well with an open top, a damaged casing, or a soakaway pit next door offers very little protection regardless of how clear the water appears when it comes up.

Understanding what is in your water and what the parameters mean is the first step. The second step is actually testing yours.

For a complete guide to how to test your borehole or well water in Nigeria, what options are available across different locations and budgets, how to collect a sample correctly, and exactly what to do when results come back, read our companion article: How to Test Your Borehole Water in Nigeria: Practical Options for Every Budget and Location.

Jay Water Advisory is committed to promoting sustainable water and environmental practices for communities across Nigeria and beyond.