Rain Water 101

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Our Water is Valuable

High quality fresh water is gaining value as a community resource.

Water Rich Region

CSOThe river system at Pittsburgh carries about 7,000 BGY (billion gallons per year) of water past our city. Another 40 BGY of water reaches the city as rain. While our region is rich in water, we face challenges to the quality of our water. Rainfall is clean, but once on the ground, water becomes contaminated with pollution and needs to be treated. Our history of industrial contamination and the ongoing inflow of sewage into our rivers challenge our water authority, Pittsburgh Water and Sewer Authority (PWSA) as they deliver safe drinking water that meets  modern health standards.

Mixing Waste and Water

Because of our abundance of water and relatively low costs, we are often wasteful in our usage. Water reaching our taps is of very high quality and is consistently safe to drink, yet we drink less than one percent of the water we use at home.  At the same time, all the high quality (drinkable) water we use for showers, laundry, dishes, and cleaning has to be treated again by the sewage treatment plants at Alcosan before it can be released back to the rivers. This water moves through thousands of miles of pipes and many of those pipes are at the end of their useful life.

Our Water is Hidden

In the past, we solved our rainwater problems underground.
It’s time to think differently.

Pittsburgh’s Sewer System

We-Used-to-ThinkAs more Pittsburgh residences installed indoor plumbing in the late 19th century, the City developed a plan to better manage wastewater.  We piped all waste water underground and directed those pipes downhill to the nearest valley stream.  Streams were buried in place using giant tunnels and roads built on top. Rainwater runoff captured at street inlets lead to the same network of pipes.  This is the basis of a Combined Sewer System. 

Currently, our Combined Sewer System flushes sewage into the rivers on a regular basis and one of the region’s biggest challenges is to fix the system and limit the overflows. 

Crisis To Action

Washington Boulevard-Then

The city’s struggle with flooding in Washington Boulevard is nothing new. During the flood of 1952, the Pittsburgh Press reported “some 50 autos were stranded…city officials reconsidered a $785,000 storm sewer plan but decided it cost too much.”

Washington Boulevard-Now

Pittsburgh-flash-floodOn August 11, 2011 a similar circumstance happened on the Boulevard for when two adults and two children died when their cars became submerged in 9 feet of water during a 2 inch storm in the East End. Pittsburgh was once again faced with the problem that we thought we had “buried” decades ago. The region will have to invest billions of dollars to upgrading our rainwater infrastructure to prevent future tragedies. Green infrastructure can help rainwater performance and create more beautiful communities.

An Expensive Solution

Pittsburgh and many older cities are under federal Consent Decrees to end Combined Sewer Overflows (CSOs). The solution to this is expensive.  It is estimated that Allegheny County will have to spend almost four billion dollars to correct the problem.  Some of the proposed solutions involve even bigger buried pipes and treatment plant expansion to manage all the rain falling on the region.  Increasingly, people are feeling that such an enormous investment should be made within our communities – not just underground – reintroducing streams, ponds, and wetland gardens so that rainwater can be managed within the landscape while creating new public amenities.

What is Green Infrastructure?

Green infrastructure is a set of strategies for bringing greater ecological function into urban environments and rethinking the existing infrastructure of cities in new, more sustainable ways… it involves redesigning urban infrastructure—particularly stormwater and drainage systems— to more closely resemble natural drainage patterns that encourage groundwater infiltration, evapotranspiration and water quality improvement through filtration.

Many different techniques have been developed for creating artificial wetlands, rain gardens, and other interventions into the conventional, street/gutter/drain/pipe system of urban stormwater management.

We Need to Address Rainwater Issues
at Multiple Scales



Property specific. Not able to retain the entire property’s water in a major storm event.


Has the ability to retain the rain water for large+shared properties. Sometimes requires collaboration between multiple property owners/managers.


Is able to hold water that is conveyed through streetscape strategies. With community and municipal support, it can be stored for reuse.


A large system of infrastructure that has a high capacity for rainwater storage that is fed from the previous scales and can serve as an amenity for multiple neighborhoods.


Infrastructure that networks the multiple watershed systems in the region. Currently that role is being fulfilled by ALCOSAN

Green Infrastructure Toolkit

These cards from our toolkit demonstrate water management strategies at the various scales.

Links & Resources

Resources by Living Waters of Larimer for Download

Links to other rainwater resource providers