Office National de l'Assainissement du Sénégal (ONAS)

What Office National de l'Assainissement du Sénégal (ONAS) does

ONAS (Office National de l'Assainissement du Sénégal) is the Senegalese national sanitation utility, established in 1996 by law n° 96-02 as a public industrial and commercial establishment (EPIC) under the supervision of the Ministry of Water and Sanitation. Headquartered in Dakar with 157 employees, ONAS holds a statutory monopoly over wastewater collection and treatment, stormwater drainage, and flood prevention across all 16 regions of Senegal. Its core technical assets include trunk sewer networks, treatment plants, and flagship depollution works such as the Hann Bay project (serving over 500,000 beneficiaries) and the 82 billion FCFA Hann-Fann collector. The organization also executes major peri-urban projects such as the 23 billion FCFA Touba sanitation scheme, extending service to secondary cities with high seasonal demand from religious tourism.

ONAS operates a hybrid public utility revenue model combining three funding streams: (i) the Redevance d'Assainissement, a regulated sanitation fee paid by households and commercial users, which the Director General has acknowledged grows only 1–2% annually and is insufficient to cover operating costs; (ii) direct allocations from the Senegalese state budget, with a triennial envelope of 200 billion FCFA underwriting capital expenditure; and (iii) concessional co-financing from a broad multilateral and philanthropic lender base including the World Bank, African Development Bank, JICA, Islamic Development Bank, BOAD, BADEA, and the Bill & Melinda Gates Foundation. This blended structure allows ONAS to mobilize investment multiples beyond its fee revenue.

The organization has been recognized internationally as the leading sanitation operator in sub-Saharan Africa. Governance is exercised through a Director General appointed by the state — Dr Cheikh Dieng was appointed in May 2024 and succeeded by Séñy Diène in February 2025 — operating within the policy framework set by the supervising ministry. ONAS's strategic agenda centers on extending geographic coverage, modernizing treatment infrastructure, and protecting coastal and urban water bodies from pollution-driven degradation.

Name

Office National de l'Assainissement du Sénégal (ONAS)

Legal name

OFFICE NATIONAL DE L'ASSAINISSEMENT DU SENEGAL (ONAS)

Website

https://onas.sn

Company type

Private

Founded year

1996

Operating status

Operating

Headcount range

101–250 employees

Short description

ONAS is Senegal's state-owned national sanitation utility, holding a statutory monopoly over wastewater treatment, stormwater drainage, and flood prevention across all 16 regions, funded by sanitation fees, state budget allocations, and multilateral donor financing.

Ownership category

akta.pro rank

Product category

Public Sanitation Services

NAICS

Water, Sewage and Other Systems (2213), Sewage Treatment Facilities (22132), Sewage Treatment Facilities (221320), Administration of Air and Water Resource and Solid Waste Management Programs (924110), Administration of Environmental Quality Programs (9241)

SIC

Sanitary Services (4950), Electric, Gas & Sanitary Services (4900), Water, Sewer, Pipeline, Comm & Power Line Construction (1623)

akta.pro primary industry

Water Supply & Wastewater Utilities Administration (BPAIACAG)

akta.pro secondary industries

Emergency Response & Sewer Repair (Blockages, Collapses) (EUANACAL), Water, Sanitation & Hygiene (WASH) (BPAGABAC), Water & Wastewater Compliance (NPDES/Stormwater, Pretreatment, Drinking Water/SDWA) (EUAHABAB), Onsite/Decentralized Reuse Utilities (District/Building‑Scale Reuse as a Service) (EUANAGAH)

Keywords

• Public sanitation services
• Wastewater management
• Stormwater drainage
• Sanitation infrastructure
• Sewer network operations

Headquarters

HQ city

Dakar

HQ country

Senegal

HQ region

Africa

Offices1 record

Markets served

GTM type

B2C

Offering type

Services

Cost components

Infrastructure, Operations, Personnel, Technology or R&D, Others

Revenue model

1. Public sanitation fees (Redevance d'Assainissement): ONAS collects sanitation fees (redevance de l'Assainissement) from users as a regular revenue stream. The fees grow linearly between 1-2% annually, which the DG noted is insufficient to cover exponential growth in infrastructure investments.

Distribution channels1 record

Marketing channels6 records

Core offering

ONAS is Senegal's national public sanitation utility responsible for planning, designing, operating, and maintaining wastewater and stormwater infrastructure across urban and peri-urban areas. Its core work covers wastewater collection and treatment, storm water drainage operations, development of autonomous on-site sanitation, and valorization of treatment plant by-products (such as treated wastewater reuse and sludge processing). It also delivers flagship infrastructure programs including the Hann Bay depollution project, the 10 Cities Sanitation Program, and the World Bank-funded PEAMIR rural water and sanitation project.

Product overview

ONAS (Office National de l'Assainissement du Sénégal) is a public industrial and commercial establishment responsible for sanitation sector management in Senegal. Created by law n°96-02 of February 22, 1996, ONAS operates as a unified service portfolio rather than a modular software platform. The organization's core offerings comprise wastewater collection and treatment infrastructure, storm water drainage systems, autonomous sanitation development, and by-product valorization from treatment plants. Major infrastructure projects include the Hann Bay depollution initiative, the 10 Cities Sanitation Program, and rural water and sanitation projects (PEAMIR). ONAS also operates public services such as sewage connection requests, complaint handling, and a sludge vacuum call center.

Differentiator

Problem solved

Functional benefit

Products and services

• Gestion des eaux usées (Wastewater Management)
• Gestion des eaux pluviales (Storm Water Drainage)
• Assainissement autonome (Autonomous Sanitation)
• Valorisation des sous-produits (By-product Valorization)
• Stations d'épuration (Wastewater Treatment Plants)
• Centre d'appel boues de vidange (Sludge Vacuum Call Center)

Quantifiable outcome

• Hann Bay depollution project execution rate at 67% with 500,000+ beneficiaries targeted
• +2 more outcomes

Segments4 records

Ideal customer profiles4 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Partnerships

Eight partnerships are on record, tiered core, minor and major.

• Speak Up AfricacoreStrategic or Co-development Partner · 1 January 2016Partnership initiated in 2016 to support communication and advocacy components for the sludge management market structuring program (PSMBV) in Pikine and Guédiawaye, including media campaigns, social mobilization, and behavioral change communication.
• WSP (Water and Sanitation Program)minorStrategic or Co-development PartnerWSP, part of the World Bank Group, supports sanitation sector development programs.
• Association des Acteurs de l'Assainissement (AAAS)coreChannel Partner/ Reseller/ DistributorAssociation of sanitation operators collaborates with ONAS on vacuum sludge call center operations and mechanized sludge services in Pikine and Guédiawaye.
• Port Autonome de DakarmajorStrategic or Co-development PartnerCollaboration on Hann Bay depollution project, signed protocol of agreement for joint environmental remediation efforts.
• SONATELminorGTM or Marketing PartnerQuality of services collaboration between ONAS and SONATEL, Senegal's national telecommunications operator.
• SONAGED (Société Nationale de Gestion Intégrée des Déchets)minorImplementation/ SI/ Consulting PartnerONAS requested SONAGED intervention to establish effective waste collection systems supporting sanitation infrastructure maintenance.
• ASN (Autorités de Sûreté Nucléaire) - Senegal Nuclear Safety AuthorityminorStrategic or Co-development PartnerPartnership convention signed for regulatory and safety collaboration in sanitation sector.
• UCG (Université Cheikh Anta Diop de Dakar)minorStrategic or Co-development PartnerPartnership convention with UCAD for academic and research collaboration in sanitation sector.

Scale indicators13 records

Recent moves7 records

Expansion highlights4 records

Direct peers

• National Water and Sewerage Corporation (NWSC) - Uganda: Uganda's statutory national water and sewerage utility, serving as the East African counterpart to ONAS. Comparable in scale, mandate (water + sewerage), public-utility governance, and donor-funded capex model.
• SNDE (Société Nationale de Distribution d'Eau) - Niger: Niger's national water distribution utility operating under state supervision. Comparable as a Francophone West African public utility with similar funding-mix constraints and urban/rural service-mandate dynamics.
• SDE / Sénégalaise des Eaux: Senegal's private water distribution operator (formerly Veolia/Suez concession), distributing water in urban Senegal under a public-service delegation contract with SONES. Comparable as a sanitation-adjacent operator inside ONAS's service territory and regulatory perimeter.
• ONEA (Office National de l'Eau et de l'Assainissement) - Burkina Faso: Burkina Faso's national water and sanitation utility with an almost identical name, mandate, and EPIC legal structure to ONAS. Closest functional peer in West Africa, operating urban water/sanitation services under state supervision.
• SONES (Société Nationale des Eaux du Sénégal): Senegal's national water infrastructure authority, operating under the same Ministry of Water and Sanitation as ONAS. Directly comparable as a state-owned EPIC managing national-scale water/sanitation infrastructure with a parallel regulatory mandate.
• Addis Ababa Water and Sewerage Authority (AAWSA): Ethiopia's capital-city water and sewerage authority, operating one of Africa's largest urban sanitation networks. Comparable mandate (urban water + sewerage), public-authority governance, and donor-funded capex profile.
• Ghana Water Company Limited (GWCL): Ghana's state-owned urban water utility, responsible for potable water production and distribution nationwide. Comparable as a large African national utility with similar government-budget-plus-donor funding dynamics and operational scale challenges.
• JIRAMA (Jiro sy Rano Malagasy): Madagascar's state-owned water and electricity utility, operating under similar EPIC-style public-utility governance with chronic underfunding and donor dependency. Comparable as a Francophone African national utility facing analogous structural challenges.

Broad incumbents

• ONEE - Branche Eau (Office National de l'Électricité et de l'Eau potable) - Morocco: Morocco's national multi-utility (electricity + potable water), with a broader mandate than ONAS but operating the most mature national water utility in Francophone Africa. Comparable as a large incumbent with superior operational and financial maturity.
• Veolia Africa (Suez/Africa Water & Sanitation): Multinational water and sanitation operator active across Africa (including past Senegal concessions). Comparable as a sophisticated private-sector sanitation operator that competes with public utilities for delegated management contracts.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat4 records

Key risks6 records

Key highlights7 records

Customer concentration

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Revenue estimate

Valuation estimate

Number of profiles

Profiles4 records

Funding overview

Funding rounds

Investors

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M&A

Investments

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Frequently asked questions about Office National de l'Assainissement du Sénégal (ONAS)