New and redeveloped building projects will have to meet more stringent flood prevention requirements , said national water agency PUB on Monday.

For example, all industrial, institutional, commercial and residential projects with land sizes larger than 0.2ha will have to include features to slow down and retain rainwater, such as detention tanks and green roofs. This requirement will lessen the likelihood of flash floods and takes effect from January 2014.

From June this year, buildings in low-lying areas that cannot meet the minimum crest and platform levels will also have to have flood barriers to prevent them from being flooded. PUB had announced earlier that these buildings were required to have flood protection measures but is now specified that these measures must come in the form of flood barriers.

The PUB will enforce these new regulations by checking the projects' plans when they are submitted for approval. These new rules will not be retroactively applied to existing building projects until they are redeveloped.