Sixty outbreaks from splash pads, and Cryptosporidium caused nine tenths of the cases

Splash pads are recreational water venues that spray or jet water at
users, intended mainly for young children. Because the water is sprayed rather
than stood in, they are often treated as outside pool rules — and children in
nappies use them.

Between 1997 and 2022, public health officials from **23 states and Puerto
Rico** reported 60 waterborne disease outbreaks associated with splash
pads.

What they caused

One organism accounts for nearly all of it

**40 of the 60 outbreaks (67%) were confirmed to be caused, at least in part,
by Cryptosporidium.** Those 40 produced:

• 9,622 of the 10,611 cases — 91%
• 123 of the 152 hospitalisations — 81%

Cryptosporidium is the reason splash pads are a public health subject at
all. It is a parasite with a tough outer shell that **survives chlorine at the
concentrations used to treat recreational water**, so the disinfection that
handles most pathogens does not handle this one. One child with diarrhoea can
contaminate a system that then sprays it at everybody else.

Two outbreaks suspected to be caused by norovirus produced **72 of the 99
emergency department visits — 73%** — a small number of outbreaks with an
unusually high rate of people needing urgent care.

How the data exists at all

**Waterborne disease outbreaks have been voluntarily reported to the CDC by
state, local and territorial health departments since 1971**, originally on a
standard paper form, and **since 2009 through the web-based National Outbreak
Reporting System**.

Voluntary is the word to hold. Sixty outbreaks over twenty-five years is what
was reported, not what happened.

*Source: Lawinger H, Khan A, Lysen C, et al. Waterborne Disease Outbreaks
Associated with Splash Pads — United States, 1997–2022. MMWR Surveillance
Summaries, Centers for Disease Control and Prevention.*