The pattern growth of Leptolyngbya (plectonema)  nostocorum on layer of  porcelain of washing basin was remarkable, such finding  attracts our interest to conduct  this research. Despite the unfavorable conditions, the growth of alga was not affected. It was  subjected to pressure as a result  of   flowing  of water  from tap with ranges from 0.1- 7.6  liters per minute. This process is daily repeated for about 10 times a day for periods of up to 2.5 hours. The light intensity was 100 lux and the temperature ranges between 25- 30 ºC as a result of process of opening and closing the tap, respectively. In addition to the previous stress, organism has been exposing to the amount of liquid soap to wash hands as a result of daily non-stop process of human activities. Description and identification of algae has been made. Basic physical and chemical analysis of tap water has been also conducted, drinking water in Saudi Arabia is stored in underground tanks and replenished as water runs out. The analysis of the water showed that pH was alkaline  (8.7) and the total soluble salts was 56.7mg/L. The total alkalinity  was 28  mg/L as well as the total hardness was 18 mg/L, Calcium hardness, Magnesium hardness were 14, 4 mg/L, respectively. Calcium, Magnesium and Chloride are represented at concentrations of 5.6, 0.96 and 4 mg/L, respectively. The concentration of nitrate was 0.56 and the concentration of iron was 0.18 mg/L. For the growth curve of alga, the best growth (0.271, 2630.46 mg/L) was achieved  for optical density, dry weight, respectively after 16 days of incubation. For different concentrations of the detergent,  it was found that the least concentration did not have any inhibition zone to the growth of alga was 0.2%. Above this concentration, there has a steady increase in the diameter of inhibition zones.