How many survey response capacity does 1 project has in humanitarian?

I want to conduct household survey of about 1 lakh houses. Does it support about 100000 houses?

Kindly please be informed that the OCHA server is able to support unlimited data. But you (i.e. your user account) should also be able to demonstrate that your survey project is for the humanitarian cause.

we have been working on the project supported by US-AID here in Nepal for municipalities in Nepal. how to demonstrate that ?

You may have to provide evidence that supports the same. But please be informed that it’s not now that you have to provide the information. It’s only if and when needed. Maybe you could also use multiple user accounts to collect the data so that your project does not affect the performance of the KoBoToolbox server.