The organisation, which spends £2 million on above-the-line UK advertising, is in the process of drawing up a shortlist ahead of a pitch for the business. AAR is co-ordinating the review.
Sources close to the pitch suggested that WaterAid, which has traditionally focused its advertising on DRTV, is talking to agencies about a brand campaign.
WaterAid has previously worked with agencies including Kitcatt Nohr Digitas and The Good Agency on ad projects. Watson Phillips Norman has handled direct.
Last year, WaterAid launched its Big Deal Appeal, which won support from media owners including UTV Media and GMG Radio. Presenters on radio stations encouraged listeners to sponsor them and donate to WaterAid in a bid to raise £1.2 million towards providing clean water and sanitation to more than 134,000 people in Malawi.