This study examined three drinking water reservoirs in China to understand how antibiotic-resistant bacteria spread through water and sediment. Researchers found that mobile genetic elements (like integrons) play a bigger role than antibiotics themselves in spreading resistance genes among bacteria. One reservoir, Jian’gang, naturally removed most resistance genes as water flowed through, suggesting its natural purification processes are quite effective. Understanding how these factors work together helps protect drinking water supplies from antibiotic-resistant bacteria.