Equity is of great relevance to developing irrigation. Its two dimensions —horizontal in regard to water distribution to farmland and vertical in terms of productivity differences between farm categories — are studied in two irrigation systems, an old farmer‐managed and a new government‐agency‐managed system. Equity in the distribution of irrigation water differed between abundant and scarce water supply conditions. Paddy grown during the monsoon season when water is available in abundant quantity shows that there was a reasonable degree of fairness in its distribution between head and tail reach farmland. However, wheat grown in the dry season with limited supply of water rendered evidence of unfair distribution demanding better management of irrigation water. The analysis of vertical equity shows that small farms are more efficient than large ones in increasing productivity through the use of irrigation facilities.