The impact of both current (Na- and P-rich water) and emerging (K-rich) wastewaterapplications on soil fertility, soil physical and chemical properties is not well known. Irrigationwith treated wastewater has potential for both positive and negative consequences for soilproperties. For this study, background surveys were conducted to assess winery watertreatment methods and volumes, as well as types and amounts of cleaning agents used.Monthly winery wastewater samples are collected to represent water leaving the winerybefore treatment and after treatment. Basic water chemistry analysis includes pH, electricalconductivity (EC), and concentrations of anions (Cl-, NO3-, SO42-, and HPO42-) and cations(Ca2+, Na+, K+, Mg2+), measured via ion chromatography. The sodium absorption ratio (SAR)and potassium absorption ratio (PAR) have been determined. Additionally, the water isanalyzed for total organic carbon and biological oxygen demand (BOD). This approachpermits evaluation of the treatment method, as well as an understanding of temporal shiftsin wastewater composition. Generally, the EC of the effluent of very large wineries (1mil. gal/yr production or more) has been 1000-2100 uS/cm, whereas small to medium (Less than 1mil.gal/yr) have fallen within the 200-800 uS/cm. EC values, and other measured parameters,vary seasonally, reaching highs usually during October. Column experiments are ongoing tocompare the effects of Na-rich and K-rich solution chemistry on soil dispersion and hydraulicconductivity. Soil mineralogy is hypothesized to exhibit a large influence on the effect of K insoils. To examine this relationship, these experiments will be conducted with vineyard soils ofdiverse mineralogy, from the Napa and Lodi region, to simulate the effects of irrigation with K-rich winery wastewaters.