## 1 Introduction  
Choosing the most appropriate material for manufacturing water pipes that are both durable and non-toxic but still cost-effective is a challenging task in the wastewater industry. Commonly used pipe materials include concrete; metals such as stainless steel, copper, and ductile iron; and plastics such as polyvinyl chloride (PVC), cross-linked polyethylene (PEX), and high-density polyethylene (HDPE) [1]. Copper, a material often used in the construction industry for water transportation and refrigerant channeling in heating and cooling systems, stands out due to its unique properties. Its strength, reliable connections,and exceptional corrosion resistance make it a preferred choice for manufacturing wastewater pipes, and its UV resistance allows for above-ground installation [2]. While living organisms need low concentrations of copper because of its cofactor functions for many enzymes and metalloprotein, at higher concentrations, this metal can become toxic and inhibit the growth of microorganisms [3; 4; 5].  
Copper ions' antimicrobial properties can be explained by their ability to damage bacterial cell walls, obstruct metabolic activities, and cause oxidative stress, which results in cell death [6; 7]. Its antimicrobial properties are mainly seen in the main biocidal form of copper, the cupric ion (Cu\({}^{2+}\)) [8], which forms when Cu is released through corrosion [6; 9]. Because of this, the antimicrobial properties of copper can aid in reducing water pollution, particularly in household water supplies, that forms due to the infiltration of chemical and biological contaminants. Pathogens from human and animal waste, sewage overflows, agricultural runoffs, and industrial discharges primarily cause bacterial contamination in domestic water systems. Inadequ wastewater treatment and the leaching of contaminants into groundwater and surface water sources further contribute to the problem. This contamination introduces harmful bacteria, viruses, and parasites into water systems, which can infiltrate homes and pose serious health risks to inhabitants.  
The most common pathogens include _Enterococcus faecalis_[10], _Escherichia coli_[11], _Vibrio cholerae_, and _Salmonella typhi_, and are responsible for numerous waterborne diseases [12; 13]. Their presence affects water quality, leading to changes in taste and odor [14; 15]. Biofilms, multicellular aggregates containing an extracellular matrix, make biological water contamination even more severe [16; 17; 18]. In various industry sectors, particularly water distribution and pipeline systems, these bacterial communities are challenging to eradicate since they can adhere to surfaces and form dense, protective matrices highly resistant to chemical and physical interventions [19; 20]. Consequently, their formation leads to biofuling, a process in which their accumulation reduces the quality of fluid flow [21].  
While earlier research has shown that copper sulfate and, to a lesser degree, copper nitrate have antimicrobial qualities, the majority of these studies have concentrated on the bactericidal effects of these substances alone or on a small number of pathogens. By directly comparing the two compounds over a broad concentration range, this study aims at filling a gap by evaluating not only their antibacterial properties but also their effects on biofilm formation and profiles of antibiotic resistance. This is especially important for pipeline and wastewater systems, where biofilm resilience and sublethal exposure are prevalent issues.