Lived sanitation experiences in informal and formal settlements in Nairobi, Kenya: A comparative study through the lens of the Human Right to Sanitation.

Urban sanitation is essential for health and well-being, yet provision remains deeply unequal, particularly in informal settlements. This study compares lived sanitation experiences across Nairobi's informal and formal settlements and examines how water insecurity - too much, too little, too dirty water - intersects with sanitation. We combined eight focus group discussions (n = 65 participants) with household surveys (n = 545) to analyse disparities across Human Right to Sanitation (HRtS) normative content dimensions of availability, accessibility, quality, safety, affordability, and acceptability. Nearly all surveyed households in formal settlements have private, sewered facilities, whereas in informal settlements, private toilets are rare, often poorly constructed, shared, and unsafely managed. Low incomes, insecure land tenure, and user fees constrain infrastructure investment and maintenance, further restricting HRtS realisation. Sanitation systems in informal settlements are highly vulnerable to water insecurity, which can compromise waste containment and hygiene, with potential implications for exposure to waterborne diseases. In formal settlements, sewered systems limit disruptions, but water insecurity can compromise sanitation functionality and maintenance, while excess water can trigger sewer overflows and short-term service disruptions. HRtS realisation requires attention to all normative dimensions, integrating resilient infrastructure, safe faecal waste management, participatory governance, and community involvement, with attention to vulnerable groups, including women, children, and low-income households. Climate-resilient, systems-oriented approaches are essential to prevent faecal contamination, maintain service continuity, and support equitable health outcomes. By highlighting interactions between sanitation and water insecurity, this study provides actionable insights for designing urban sanitation systems that safeguard human rights, health, and dignity in rapidly urbanising cities.