Does the stormwater line on your PWSA bill feel like money washed down the drain? If you own a home in Pittsburgh, that charge is tied to your roof, driveway, and other hard surfaces. With a few smart landscaping moves, you can shrink the fee and improve your yard at the same time. This guide shows you exactly how PWSA calculates your bill and the practical steps to lower it with projects that meet local rules. Let’s dive in.
How PWSA calculates your fee
PWSA bases your stormwater fee on impervious area, measured in Equivalent Residential Units (ERUs). One ERU equals 1,650 square feet of hard surfaces like roofs and driveways. Residential properties fall into tiers by ERUs, while non-residential properties are billed per ERU. You can find the definitions and credit rules in the PWSA Stormwater Fee Credit Manual.
PWSA publishes tiered monthly rates. For example, 2024 residential tiers are shown in the Stormwater Fee FAQ, and you should confirm current rates there before making decisions. PWSA mapped impervious areas using aerial imagery, and you can ask them to review the data if something looks off.
- Learn how PWSA credits work in the Stormwater Fee Credit Manual: residential and non-residential standards
- See current stormwater fee FAQs and rate examples: PWSA Stormwater Fee FAQ
Two proven ways to lower your bill
Reduce impervious area
When you remove or convert hard surfaces, you may drop into a lower residential tier or reduce ERUs. Common moves include removing unused concrete, replacing a paved patio with planting beds, or using permeable pavers with an infiltration base. PWSA may exclude properly designed permeable pavement from your impervious area count, even if it does not qualify for a separate credit. See the FAQ for details on what counts.
Earn a PWSA credit with green infrastructure
Homeowners can cut the stormwater charge by 50 percent by installing a measure that captures and detains 0.75 inch of runoff from the property’s impervious area, then releases it slowly within 24 to 72 hours. Qualifying options include rain gardens, dry wells, cisterns or underground storage, green roofs, and downspout disconnection routed into one of these systems. The credit applies only after you apply and receive approval from PWSA. Review the technical requirements in the credit manual before you design.
- Get the rules and example calculations: Stormwater Fee Credit Manual
What qualifies: a simple sizing guide
PWSA uses a straightforward formula to size residential systems. You must detain 0.75 inch of runoff from your impervious area and drain within 24 to 72 hours. The manual provides the formula and worksheets you can follow.
- Volume formula: Impervious area (sq ft) × 0.0625 × 7.48 = gallons to detain.
- Example: A home with 2,000 sq ft of impervious area must detain about 935 gallons to qualify.
Eligible practices include rain gardens, dry wells, underground storage or cisterns, and green roofs. Simply disconnecting downspouts to your yard does not qualify. Downspouts must be routed into a qualifying BMP to earn the credit.
- Confirm what counts and how to document it: Stormwater Fee Credit Manual and PWSA Stormwater Fee FAQ
Easy starter win: the rain barrel credit
You can claim a one-time $40 credit for installing a rain barrel of at least 50 gallons that is connected to a downspout. This is separate from the 50 percent residential credit. Submit the simple application with a photo of your installed barrel.
- Apply here: Rain Barrel Credit Application
Step-by-step: from idea to credit on your bill
- Check your property’s impervious area and tier. Review your bill and PWSA resources. If you see an error, contact PWSA to request a review.
- Choose your strategy. Decide whether to remove hard surfaces, install a qualifying BMP, or do both.
- Size the solution. Use the 0.75 inch rule and PWSA formula to calculate the required storage volume.
- Install and document. Take photos, keep receipts, and sketch a simple site plan showing downspouts and the BMP.
- Apply for the credit. Use PWSA’s Stormwater Credit Program to submit your application and supporting documents.
- Maintain and renew. Credits last three years. Submit a renewal with a current photo and inspection report when PWSA reminds you.
- Start here for forms and program details: Stormwater Credit Program
Costs, savings, and practical ROI
Small DIY rain gardens often cost $5 to $15 per square foot for plants and soil work. Many homeowners spend under $1,000 for a simple garden, while professionally installed systems can cost a few thousand dollars depending on site conditions. For more context, see this overview of rain gardens and installation basics.
- Learn the basics of rain gardens and typical costs: What is a Rain Garden?
Savings depend on your tier and the credits you earn. Using PWSA’s 2024 residential rates as an example, a Tier 2 bill at $10.06 per month drops to $5.03 per month if you either move to Tier 1 or qualify for the 50 percent credit. That saves about $60 per year. Payback can be long if you look only at the fee, so also weigh co-benefits like less runoff, fewer yard drainage issues, and a healthier landscape.
- See current rate examples and program FAQs: PWSA Stormwater Fee FAQ
Local help and resources
- PWSA program hub: applications, manuals, and FAQs to guide your project and credit submission. Start with the Stormwater Credit Program and the Stormwater Fee Credit Manual.
- Grow Pittsburgh: education and garden support that can help you design a practical rain garden and connect to local workshops. Explore their program updates and guidance.
- Penn State Extension: homeowner-friendly resources on stormwater credits, rain gardens, and barrels. Read their stormwater credit overview.
Selling soon? Think like a buyer
In Allegheny-West and across the city, buyers notice a well-landscaped yard and clear utility costs. If your property shows reduced hardscape, a functional rain garden, and a documented PWSA credit, it signals care and may help your home stand out. Before you list, decide which upgrades will matter most in your price bracket and neighborhood, then time the work so the credit appears on your bill during showings.
Ready to map out a cost-effective plan for your home? Reach out to Kevin C. Schwarz, Real Estate Agent for neighborhood-specific advice, vendor connections, and a strategy that aligns with your goals.
FAQs
How PWSA calculates stormwater fees in Pittsburgh
- PWSA charges based on impervious area using ERUs, with one ERU equal to 1,650 square feet and residential tiers set by your mapped area.
Which landscaping projects qualify for a 50% PWSA credit
- A system that captures and detains 0.75 inch of runoff from your impervious surfaces and drains within 24 to 72 hours can qualify when you apply and are approved.
Do permeable pavers reduce my PWSA bill
- When designed with an infiltration base, PWSA may exclude permeable pavement from impervious area counts, which can lower your tier even if it does not earn a separate credit.
Does a rain barrel count toward the stormwater fee credit
- A rain barrel of at least 50 gallons connected to a downspout qualifies for a one-time $40 credit, which is separate from the 50 percent residential credit.
How long do PWSA stormwater credits last
- Credits are valid for three years, and you must renew with a current photo and owner inspection to keep the credit active.
