## 1 Introduction  
Thailand is a Southeast Asian country connected to its neighboring countries, namely Myanmar to the west and north, Laos People's Democratic Republic and Cambodia in the east, and Malaysia to the south. In general, there are four regions classified by topography: the north, central, northeastern, and southern regions. Southern Thailand is quite unique compared to other regions, since the region is a peninsula surrounded by the Andaman Sea on the western side and the South China Sea on the eastern side. This region in located in a tropical zone with heavy rainfall throughout the year. The rainy season in the southern region is different from that in other parts of Thailand; abundant rain occurs during both the northeast and southwest monsoons. The number of rainy days and rainfall (mm) in the southern region are higher than in the upper parts of Thailand. The numbers of rainy days in the south during the 1981-2010 period were 145 and 178 days for the east and west coasts, respectively, whereas the numbers of rainy days in other regions were in the range of 110 to 130 days [1]. During the monsoon season, this region suffers from floods that detrimentally affect residences and human health due to the increase in pathogenic microbes after the disasters. Indoor biological agents such as bacteria, fungi, viruses, mites, and their toxic substances and metabolites can have adverse human health effects [2]. Increased concentrations of airborne fungi have been reported in flood-damaged homes [3,4]. Under flood conditions, the water content in the air becomes high, promoting fungal growth in indoor environments [5].  
Increased indoor fungal levels in water-damaged homes create risks for human diseases such as respiratory illnesses and allergies [5,6]. Exposure to indoor fungi can occur via inhalation of airborne fungal spores and/or allergenic substances that can induce immunoglobulin E (IgE)-mediated hypersensitive reactions [7]. Indoor fungal exposure can impact human health and lead to respiratory infection, irritation, allergy, and asthma [8,9]. Indoor humidity is another factor that can increase levels of abiotic pollutants such as formaldehyde [10,11]. Such abiotic pollutants may exacerbate human health issues synergistically with biotic substances, including fungal allergens.  
Previous studies have reported indoor airborne fungi in water-damaged homes [4,12,13,14,15]. For instance, one study reported that levels of fungal spores in flooded homes in New Orleans, USA were significantly higher indoors than outdoors and in non-flooded homes [12]. A study conducted in Taiwan reported increased concentrations of airborne fungi and altered fungal assemblages after flooding [4]. In Thailand, post-flood measurements were recorded for indoor concentrations of airborne fungi in a hospital after the 2011 flood disaster [13,14].  
Previous studies have reported indoor airborne fungal concentrations in Thailand [14,15,16]. However, little is known about fungal assemblages on surfaces in homes in Thailand. It is important to characterize the compositions and diversities of indoor visible molds, since they are known to be associated with allergies and respiratory illnesses [17]. In this study, we report our post-flood measurements of fungal assemblages on indoor surfaces with visible mold growths in homes in Thailand. The results offer benefits for human health in terms of warning systems, intervention, and mitigation measures in post-flood implementation plans.