Harrisburg, Pennsylvania’s capital city, is home to roughly 50,000 residents within city limits and serves as the hub of a metro area of about 580,000. The city draws its drinking water from the Susquehanna River — the longest river on the East Coast and one that carries a complicated environmental history.
The water system works. It meets federal standards. But there are things worth knowing about what comes out of your tap in Harrisburg.
The Susquehanna: A River Under Pressure
The Susquehanna River drains 27,500 square miles across New York, Pennsylvania, and Maryland before emptying into the Chesapeake Bay. It’s the Bay’s largest tributary, and what happens in the Susquehanna watershed directly affects both Harrisburg’s drinking water and the health of the Bay.
The primary pressure on the Susquehanna is agricultural runoff. The watershed includes some of the most productive farmland in the Northeast, particularly in Lancaster and Lebanon counties upstream of Harrisburg. Nutrient loading — nitrogen and phosphorus from fertilizer and animal operations — feeds algal growth in the river and contributes to downstream dead zones in the Chesapeake Bay.
For Harrisburg’s water treatment, this nutrient loading means:
- Higher organic matter in source water, which increases disinfection byproduct formation
- Seasonal algae blooms that can produce taste and odor compounds
- Increased turbidity during storm events as agricultural soils wash into the river
The Treatment System
The Capital Region Water (CRW) — formerly the Harrisburg Authority — operates the DeHart Dam Water Treatment Plant and the city’s distribution system. The treatment process includes:
- Conventional coagulation, flocculation, and sedimentation
- Filtration
- Chlorine disinfection
- Corrosion control treatment (to minimize lead leaching from pipes)
- Fluoridation
CRW also manages the DeHart Reservoir, which provides supplemental supply and helps buffer against Susquehanna River quality fluctuations.
According to CRW’s water quality reports and EPA ECHO data, the system has maintained compliance with Safe Drinking Water Act standards. But several contaminant categories deserve attention.
Lead in Harrisburg’s Water
Harrisburg’s housing stock is old — the city was established in 1785, and much of the current building stock dates from the late 1800s through the mid-1900s. Lead service lines and lead solder in home plumbing are widespread.
Capital Region Water has been working on lead service line inventory and replacement as required by the EPA’s Lead and Copper Rule Revisions. The city’s 90th percentile lead levels have remained below the federal action level of 15 ppb, but individual homes can test significantly higher.
Pennsylvania has allocated substantial funding for lead service line replacement through the state’s Infrastructure Investment and Jobs Act allocations. Harrisburg has received grants for this work, but the scale of replacement needed across the city will take years to complete.
Key points for residents:
- If your home was built before 1986, assume there may be lead in your plumbing until proven otherwise
- Lead testing is available — contact CRW for information
- Running cold water before use and using cold water for cooking reduces lead exposure
Disinfection Byproducts
When chlorine used for disinfection reacts with organic matter in the Susquehanna’s water, it forms disinfection byproducts (DBPs) — primarily trihalomethanes (THMs) and haloacetic acids (HAAs). These compounds are regulated because long-term exposure at high levels is associated with increased cancer risk.
Harrisburg’s DBP levels have generally remained within EPA limits, but they fluctuate seasonally. Summer and fall — when water temperatures are higher and organic matter peaks — tend to produce higher DBP readings. The system manages this through treatment optimization and monitoring, but residents at the far ends of the distribution system may see higher levels due to longer water residence time in pipes.
Three Mile Island: The Elephant in the Room
The Three Mile Island Nuclear Generating Station sits on an island in the Susquehanna River just 10 miles downstream of Harrisburg. On March 28, 1979, Unit 2 experienced a partial meltdown — the most serious accident in U.S. commercial nuclear power history.
The 1979 accident released small amounts of radioactive gases into the atmosphere. Subsequent studies by the NRC, EPA, and independent researchers concluded that radiation doses to the surrounding population were minimal and that there was no detectable increase in cancer rates attributable to the accident.
However, the psychological impact was enormous, and public trust in official assurances about nuclear safety — and by extension, environmental safety — was permanently altered in the Harrisburg area.
Unit 1 continued operating until 2019, when it was shut down for economic reasons. Decommissioning is underway and expected to take decades. During decommissioning, monitoring of the Susquehanna for radiological contaminants continues.
Harrisburg’s water system monitors for radiological contaminants as required by federal regulations. Test results have consistently shown levels well below regulatory limits. But for many long-time residents, TMI remains a factor in how they think about their water.
Infrastructure Challenges
Capital Region Water manages not just the water system but also the city’s sewer system — and both face significant infrastructure needs. Harrisburg’s financial difficulties in the early 2010s (the city nearly declared bankruptcy) delayed infrastructure investments across the board.
CRW has made substantial progress since taking over operations, investing in system upgrades, main replacements, and treatment improvements. But the backlog of deferred maintenance in a city with 200+ year-old infrastructure is considerable.
Sewer system challenges are also relevant to water quality. Harrisburg has a combined sewer system that discharges untreated stormwater and sewage during heavy rain events. While these overflows don’t directly contaminate the drinking water supply, they affect the Susquehanna’s water quality for downstream communities and reflect overall infrastructure stress.
What Residents Should Know
- Request your CCR. Capital Region Water publishes annual water quality reports. Read them.
- Test for lead. Especially if you’re in older housing. CRW can help with testing information.
- If you notice taste or odor changes — seasonal algae in the Susquehanna can cause earthy or musty taste. It’s not harmful, but it’s noticeable. A carbon filter handles it effectively.
- Stay informed about CSO events. CRW reports combined sewer overflow events. Know when they happen and avoid recreational contact with affected waterways.
If you’re concerned about your water quality, a certified water treatment professional can test your water and advise on treatment options specific to what’s actually present in your supply.
Treatment Options
For Harrisburg homeowners looking to supplement their water quality:
- Under-sink reverse osmosis — Comprehensive removal of lead, DBPs, nitrates, and most dissolved contaminants
- Whole-house carbon filtration — Addresses chlorine taste, organic chemicals, and some DBPs
- Point-of-use lead filters — NSF/ANSI 53-certified pitcher or faucet filters provide affordable lead reduction
- UV systems — Additional disinfection for well water users in surrounding areas