Based on water chemistry analyses of five batches of water product samples from eight coalbed methane (CBM) wells of the Songhe well group in the western Guizhou province in 2017, the single-factor index method, the Nemerow index method and the health risk assessment method were used to evaluate the environmental effects of the water product. The results show that the water co-product of the Songhe well group was characterized mainly by high Na+ and Cl− concentrations, alkalinity, high total dissolved solids and Na–Cl water types. The concentrations of carcinogens (i.e., As, Cd and Cr) were low, but the non-carcinogen Ba was enriched abnormally. The single-factor index method and the Nemerow index method were used to evaluate the water co-product from the eight CBM wells, and the results show a serious pollution level of up to grade 5. The ions Na+, Cl− and Ba2+ were the main sources of pollution. The pollution is more serious in the deeper part than in the shallow part of the well group. The health risk evaluation method was used to calculate the health risk index of carcinogenic factors (i.e., As, Cr, Cd) and non-carcinogenic factors (i.e., Pd, Fe, Cu, Zn, Mn, Hg, F, Ba). The results show that the spatial distribution regularity of these metals in the well group is weak. There were mainly two CBM wells with slight risk throughout the year. With increase in drainage time, the risk gradually decreased, but in the rainy season, the risk index increased abnormally to medium risk.