Immunomodulating effect of silica-rich water represents a novel field for research, especially regarding its features toward environmental pollutants. The aim of our study was to evaluate the effects of silica-rich water intake on systemic and peritoneal inflammation in rats that were chronically exposed to the low-level microwave (MW) radiation from mobile phones. Wistar Albino rats were exposed to 900 MHz MW radiation for 3 months. The four-treatment model involved rats with standard water (SW) or experimental silica-rich water intake (EW). Peritoneal macrophages (PMs) were harvested using peritoneal lavage and divided into non-stimulated and lipopolysaccharide (LPS) stimulated subgroups. The MW-exposed rats with silica-rich water (MW+EW) had lower serum tumor necrosis factor α (TNF-α) and interleukin 2 (IL-2) levels, but higher IL-10 levels, than MW+SW rats (p < 0.05). The higher TNF-α production by non-stimulated MW exposed PMs was ameliorated by the silica-rich water (p < 0.01). The MW exposition suppressed LPS potential for TNF-α synthesis in both water type groups, with greater suppression in animals that took standard water. Our results show the modulating effect of silica-rich water toward MW-induced systemic and peritoneal inflammation, which reflects the water ability to shape monocyte plasticity, thereby altering the balance between their proinflammatory and anti-inflammatory properties.