I'd like to bring to your attention a document by WHO from 2019. It has the title "Safer Water, Safer Health" (which I think is not an ideal title; it doesn't say anything about sanitation...).

It is packed full with important information and data. 

Here is the link:  www.susana.org/en/knowledge-hub/resource...library/details/3744
Johnston, R., Prüss-Ustün, A., Wolf, J. (2019). Safer Water, Better Health. World Health Organization (WHO), Geneva, Switzerland, ISBN 978-92-4-151689-1

I copy from the key findings:

A large proportion of the overall diseaseburden, 3.3% of global deaths and 4.6% of
global disability-adjusted life years (DALYs), was
attributed to quantifiable effects of inadequate
water, sanitation and hygiene (WASH) in 2016.
This represents nearly 2 million preventable
deaths and 123 million preventable DALYs
annually. Children under 5 years of age are
disproportionally affected by inadequate WASH:
13% of all deaths and 12% of all DALYs in this age
group are related to inadequate WASH.
Sub-Saharan Africa remains the region with the
largest disease burden from inadequate WASH:
53% of all WASH-attributable deaths and 60% of
all WASH-attributable DALYs occur in this region,
and nearly one fifth of all deaths of children
under 5 years could be prevented with adequate
WASH. This report presents estimates of the
WASH-attributable burden of 12 major diseases,
adverse health outcomes and injuries and
evidence for links between WASH and another
14 conditions that have not yet been quantified
because of data limitations. Not all the health
effects of inadequate WASH on the diseases
assessed could be quantified, such as the wider
community risks of unsafe disposal or use of
sewage.
The report also presents selected WASH
interventions that have been shown to improve
health and complements them with available
cost–effectiveness analyses.

I've used this publication also to beef up the section on health in the Wikipedia article on WASH:
en.wikipedia.org/wiki/WASH#Health_aspects
(further work is needed, collaborators are welcome)

By adding this information into Wikipedia we improve the chances that members of the public will find good information on WASH on the internet.

Regards,
Elisabeth