The answer may be no. If there is no history of major water intrusion in your crawlspace, why would you pay hundreds of extra dollars for a sum pump. All you are doing is adding another mechanical system plus electrical to solve a problem you don’t have. The truth is that almost all crawlspace will have a drian on the low end. This is called a positive drain. The sealed crawlspace can connect to this existing drain. Any water under the barrier will still flow into the existing drain. Any water that may enter the sealed crawlspace from a plumbing leak will also go into the drain.
We at RCS take pride in working with our customers to provide honest and cost effective solutions.