Hello,
Questions on WASH are well specified in international standards from UN organisations, e.g.
UN (2015): Principles and Recommendations for Population and Housing Censuses Revision 3. United Nations, Department of Economic and Social Affairs, Statistical Division, New York: United Nations, 2017.
UN/ Eurostat (2018): Expert Group on Refugee and Internally Displaced Persons Statistics EGRIS) - International Recommendations on Refugee Statistics (IRRS), March 2018, European Union and the United Nation, Luxembourg: Publications Office of the European Union, 2018.
UNHCR (2020): WASH Monitoring Systems for Refugee Settings
https://wash.unhcr.org/unhcr-wash-monitoring-systems-for-refugee-settings/
UNICEF (2019): MICS6 Standard Questionnaires (UNICEF), Multiple Indicator Cluster Surveys, Round 6. https://mics.unicef.org/tools?round=mics6
UNICEF/ WHO (2018): Core questions on drinking water, sanitation and hygiene for household surveys: 2018 update. New York: UNICEF and WHO, 2018. https://washdata.org/sites/default/files/documents/¬reports/2019-05/JMP-2018-core-questions-for-household-surveys.pdf
There are also special international standards (UNICEF/WHO/UNHCR) for WASH questions especially for schools, hospitals etc.
Start with specifying your WASH research questions first. THEN look for tool modules. For ex. here
http://wash.unhcr.org/download/wash-kap-survey-module-1-preparation/
