Introduction: Cleaning dishes is a daily activity in every household, which does not receive special attention by most people. Only a few of them actually read the instructions before using the detergent and usually people do not dose it. In such cases, the misusage of the cleaning agent could lead to elevated amounts of residues on the dishes, that could have some harmful effects on our health. Purpose: The purpose of our research was to determine the residual amount of surfactants – sodium dodecyl sulphate and 1,2-benzisothiazol-3(2H)-one on different materials after manual dishwashing. Besides, it was our task also to study the effect of roughness of the material on the amount and toxicity of sodium dodecyl sulphate and 1,2-benzisothiazol-3(2H)-one. Methods: To determine the amount of residue of sodium dodecyl sulphate a spectrophotometric method employing methylene blue was applied, whereas for the 1,2-benzisothiazol-3(2H)-one determination high performance liquid chromatography was used. After determining the residues of both chemicals, the toxicity measurements were done by LUMIstox instrument by measuring the toxicity of residues on luminescent Vibrio fischeri bacteria. Results: The results showed that on the wooden plate and cup there were higher residues of both sodium dodecyl sulphate and 1,2-benzisothiazol-3(2H)-one, compared to other materials like: plastic, porcelain, stainless steel and glass plate and/or cup. The residues of sodium dodecyl sulphate were on average higher by 30 % on cups, compared to plates while residues of 1,2-benzisothiazol-3(2H)-one were higher by 60 %. That proved that the rougher is the material and the deeper is the dish, the more residues remain on them. The amount of remaining sodium dodecyl sulphate on dishes after manual dishwashing caused from 1,7 % to 2,8 % inhibition of luminescence of Vibrio fischeri bacteria, while the amount of 1,2-benzisothiazol-3(2H)-one caused 7,1 % to 11,5 % inhibition. The highest percent of luminescence inhibition (99 %) was detected in the water in which the dishes were washed indicating the synergistic effect of inhibition of both compounds 1,2-benzisothiazol-3(2H)-one and sodium dodecyl sulphate, which are usually discharged in normal household waste waters. Discussion and conclusion: Due to higher detergent and biocide residues in case of rougher materials and deeper dishes, it is suggested that higher volumes of water are used for the final washing procedure, since this will result in removing a larger portion of the cleaning agent from the surface of the dish. The key element is also the dosing of detergent which should be done according to the instructions from the manufacturer. In this way, some side harmful effects on public health from dishwashing could be avoided.