Nontelephone households are implicitly treated as a static population in discussions of sampling frame noncoverage. Yet telephone service is known to be episodic for many households, who may gain or lose service as their financial situation changes or when they move. Thus the population of telephone households at any given time includes households that were recently a part of the nontelephone population. These households may be used to characterize the nature of some noncoverage errors and even to estimate their magnitude. Using a panel constructed with the 1992-93 Current Population Survey, “transient” telephone households-those who gained or lost service over the year covered by the panel-are shown to comprise over half of the panel households reporting no telephone service in either the 1992 or 1993 surveys. These households are compared with the total nonphone population and found to be similar on a variety of key demographic characteristics. Several statewide Virginia telephone surveys are used to compare households reporting “intermittent” phone service with nontelephone households surveyed through in-person interviews. Households reporting intermittent telephone service were very similar to nontelephone households in terms of health insurance coverage and other variables known to be related to telephone status.