Background Multiunit housing residents are often exposed to neighbours’ secondhand smoke (SHS). Little is known on the current systems available to protect residents in places not covered by a residential smoking ban, or what constitutes an appropriate policy approach. This study explores relevant systems and policies in Singapore, a densely populated city-state where the vast majority live in multiunit housing and discussions on regulating smoking in homes are ongoing.

Methods In-depth interviews with 18 key informants involved in thought leadership, advocacy, policy or handling SHS complaints, and 14 smokers and 16 non-smokers exposed to SHS at home.

Results The current system to address neighbours’ SHS comprises three steps: moral suasion, mediation and legal dispute. Moral suasion and mediation are often ineffective as they depend on smokers to willingly restrict their smoking habits. Legal dispute can yield a court order to stop smoking inside the home, but the process places a high evidence burden on complainants. While setting up designated smoking points or running social responsibility campaigns may help to create no-smoking norms, more intractable cases will likely require regulation, a polarising approach which raises concerns about privacy.

Conclusions Without regulations to limit SHS in multiunit housing, current systems are limited in their enforceability as they treat SHS as a neighbourly nuisance rather than a public health threat.