美国环保局正在制定越来越多的饮用水法规，而财政资源有限，这给许多小型供水系统带来了困境。在美国环保局规定的时间范围内实现法规遵从性可能是不可能的，尤其是对于小型系统。在某些情况下，《安全饮用水法案》（SDWA）允许水务公司通过获得变更或豁免，寻求额外的时间来遵守新法规。给出了偏差和豁免标准。包括26篇参考文献。

The increasing number of drinking water regulations being set by the USEPA and limited financial resources are creating a dilemma for many small water systems. Achieving compliance with the regulations within the time frames specified by the USEPA may not be possible, particularly for small systems. Under certain circumstances, the Safe Drinking Water Act (SDWA) allows water utilities to seek additional time to comply with new regulations by obtaining a variance or an exemption. Variance and exemption criteria are given. Includes 26 references.