For many Lagos residents, flooding, traffic congestion and waste management are among the most visible environmental challenges confronting Africa’s largest city.
Yet beneath the surface lies another growing concern that often escapes public attention but carries serious implications for public health and environmental sustainability, the improper disposal of sewage.
From residential buildings and commercial premises to industrial facilities, thousands of litres of wastewater are generated daily across Lagos. While much of this wastewater is expected to pass through approved sanitation systems, environmental regulators warn that illegal sewage discharge into public drains and water channels remains a significant challenge.
Experts say the consequences extend far beyond unpleasant odours and dirty surroundings.
Untreated sewage contains harmful bacteria, viruses, parasites and other contaminants capable of threatening human health and damaging the environment.
According to the General Manager of the Lagos State Wastewater Management Office (LSWMO), Engr. Adefemi Afolabi, sewage disposal involves far more than simply evacuating wastewater from homes and businesses.
“Sewage disposal refers to the safe management of wastewater and faecal sludge from the point of generation through containment, emptying, transportation, treatment and safe disposal or reuse,” he explained.
He noted that Lagos operates a sanitation value chain that includes capture and containment, emptying, transportation, treatment, and safe disposal or reuse.
Under this system, human waste and wastewater are expected to be safely contained in properly designed septic tanks, soakaways or wastewater treatment facilities before being evacuated by accredited operators and transported to designated treatment centres.
The ultimate goal, according to Afolabi, is to ensure that wastewater is treated and rendered safe before being discharged or reused.
“Therefore, the fundamental principle is that sewage must be properly contained, emptied, transported, treated and safely disposed of or reused, rather than discharged untreated into the environment,” he said.
Environmental experts have long warned that untreated sewage poses significant health risks.
When wastewater is discharged directly into open drains, canals or water bodies, it creates conditions that can expose communities to contamination and disease.
Afolabi explained that illegal sewage discharge can affect both surface water and groundwater quality, particularly in densely populated communities where large numbers of people may be exposed.
“The discharge of untreated sewage into open drains poses serious public health and environmental risks. It exposes communities to untreated wastewater and creates conditions that can compromise public health and environmental safety,” he said.
In many parts of Lagos, open drainage systems often pass through residential neighbourhoods, schools, markets and commercial centres.
During periods of heavy rainfall, contaminated wastewater can spread over wider areas, increasing the potential for human exposure.
Public health professionals warn that poor sanitation remains one of the major contributors to waterborne diseases in many developing cities.
While significant progress has been made in improving sanitation infrastructure, experts maintain that indiscriminate sewage disposal continues to undermine public health efforts.
One of the major concerns raised by environmental authorities is the misuse of storm-water drainage systems.
Storm-water drains are designed primarily to channel rainwater and prevent flooding.
However, investigations by regulatory agencies have revealed cases where sewage systems are illegally connected to drainage channels.
According to Afolabi, such practices compromise the effectiveness of drainage infrastructure and create additional environmental hazards.
“Storm-water drains are designed primarily to convey rainfall runoff and are not intended to serve as channels for untreated sewage or faecal sludge,” he stated.
The challenge is particularly significant in a city like Lagos, where rapid urbanisation continues to place pressure on infrastructure and public utilities.
Environmental experts argue that improper sewage disposal not only affects sanitation but can also contribute to environmental degradation, pollution and reduced quality of life.
To address the problem, Lagos State has established regulatory frameworks governing wastewater management.
Under the Lagos State Environmental Management and Protection Law (EMPL) 2017, property owners, residents, commercial establishments and industrial facilities are required to manage wastewater through approved and environmentally safe systems.
The law mandates buildings to have properly designed sanitation facilities, including standard septic tanks, soakaways or wastewater treatment plants where applicable.
Commercial buildings, facilities accommodating large numbers of occupants and high-rise structures are also required to install functional wastewater treatment systems.
Most importantly, the law prohibits the discharge of untreated sewage, wastewater or faecal sludge into public drains, gutters and open water bodies.
To ensure compliance, LSWMO conducts routine inspections, compliance audits and wastewater sampling across the state.
The agency also works closely with other regulatory bodies, including the Lagos State Environmental Protection Agency (LASEPA) and the Lagos State Building Control Agency (LASBCA), to address violations.
In addition, residents are encouraged to report suspected cases of illegal sewage discharge through official complaint channels.
Where violations are confirmed, enforcement actions may include the issuance of abatement notices and other regulatory measures requiring offenders to take corrective action.
As Lagos continues to grow, experts say effective wastewater management will become increasingly important to public health, environmental sustainability and urban resilience.
The challenge goes beyond government regulation alone.
Property owners, businesses, residents and sanitation service providers all have critical roles to play in ensuring that wastewater is managed responsibly.
For environmental authorities, the message remains clear: sewage is not ordinary waste.
How it is handled can have far-reaching consequences for communities, public health and the environment.
In a city striving to become cleaner, healthier and more resilient, proper sewage management may be one of the least visible but most important investments in the future.
