==Suitable conditions==
{{Climate_change
|heading1=Drought
|text1='''Effects of drought''': Water storage used up. <br>'''Underlying causes of effects''': Lack of rainfall; Leaking linings due to bad construction; Storage not sufficient for demand – tanks are too expensive for volumes of water to outlast extended dry periods. <br>'''To increase resiliency of WASH system''': Promote smaller tank structures so they are more manageable to construct and cover, while being more affordable to families; Reduce seepage due to poor construction & siting; Follow proper concreting guidelines (see drought effects on cement, below); Make tanks from cheaper lower quality materials and repair more often; Design the outlet of the tank so that there is no dead storage; Ensure the catchment itself is efficient (e.g. gutters); Improve access to micro-finance; Support the capacity of the government or private sector to be able to provide (for payment) a tankering scheme.
|heading2=Drought effects on cement tanks
|text2='''Effects of drought''': Badly made concrete and cracked linings (e.g. in tanks, dams, waterways, wells, and other structures). <br>'''Underlying causes of effects''': Less water used for curing; Impure water used for mixing. <br>'''To increase resiliency of WASH system''': Ensure adequate mixing, ratios, purity of ingredients; Minimize water content in mixture; Ensure adequate curing.
}}
Rainwater harvesting requires at least an annual rainfall of 100-200 mm. Many places in Latin America have rainfalls of about 500 millimeters per year.
- Storage is needed to bridge dry periods<br>
}}
==Resilience to changes in the environment==
====Drought====
'''Effects of drought:''' Water storage used up. <br>
'''Underlying causes of effects:''' Lack of rainfall; Leaking linings due to bad construction; Storage not sufficient for demand – tanks are too expensive for volumes of water to outlast extended dry periods. <br>
'''To increase resiliency of WASH system:''' Promote smaller tank structures so they are more manageable to construct and cover, while being more affordable to families; Reduce seepage due to poor construction & siting; Follow proper concreting guidelines (see drought effects on cement, below); Make tanks from cheaper lower quality materials and repair more often; Design the outlet of the tank so that there is no dead storage; Ensure the catchment itself is efficient (e.g. gutters); Improve access to micro-finance; Support the capacity of the government or private sector to be able to provide (for payment) a tankering scheme.
====Drought effects on cement tanks====
'''Effects of drought''': Badly made concrete and cracked linings (e.g. in tanks, dams, waterways, wells, and other structures). <br>
'''Underlying causes of effects''': Less water used for curing; Impure water used for mixing. <br>
'''To increase resiliency of WASH system''': Ensure adequate mixing, ratios, purity of ingredients; Minimize water content in mixture; Ensure adequate curing.
==Construction, operation & maintenance==