Between 1889 and 1913, housing took centre stage in hygiene enquiries. Countless surveys across Europe sought to identify specific housing problems as health hazards. This paper explores the art of housing hygiene surveys in Belgium, France and Germany. Scrutinising surveys from Berlin, Liège and Paris, I characterise two contesting survey methods. On one hand, large-scale statistical surveys such as the sanitary register of houses in Paris aimed to establish robust epidemiological evidence on the connection between structural elements (like lighting and ventilation) and tuberculosis. On the other hand, monographic surveys adopted more idiosyncratic approaches, probing the relationship of housing and health from architectural, economic, hygienic and social angles, without insisting on a single vector of explanation. Although the era of monographic housing surveys was short-lived, it illuminates the complexity of housing as an epistemic object, which even today proves challenging to assess from a public health standpoint.