Cleaning containers weekly is an effective larval control measure but is not practical with large containers such as cement jars hence these are normally cleaned yearly. Weekly cleaning of less frequently used water containers was perceived to be unnecessary and wasteful, as people either covered those containers with lids (mainly drinking water) or did nothing, as the cleanliness of water was not a concern (non-potable water). Another barrier to weekly cleaning is that containers may not be cleaned due to seasonal migration or sickness of the person responsible for their cleaning.