Sub-Domain 2 · Water Quality and Drinking Water Architecture

SD2 documents the federal-state-local regulatory architecture governing drinking water safety and surface-water quality in PA-3 — the Clean Water Act NPDES program; combined sewer overflow (CSO) regulatory architecture; municipal separate storm sewer system (MS4) stormwater permitting; the Safe Drinking Water Act Lead and Copper Rule Improvements (LCRI) compliance architecture (LCRR October 16, 2024 compliance achieved; LCRI baseline November 1, 2027; mandatory full LSL replacement by November 1, 2037); the EPA PFAS MCLs of April 2024; and the Philadelphia Water Department's 2011 Consent Order and Agreement Long-Term Control Plan (Green City, Clean Waters). PA-3 instances include PWD's 2026 LSL pilot (~1,000 replacements in North and West Philadelphia), the ~20,000-25,000 LSL inventory remaining, PFAS in the Schuylkill and Delaware source waters, and the 164-outfall CSO architecture under the 25-year compliance schedule (85% reduction target by 2036). The Both/And operative at SD2 holds both PWD's substantive compliance trajectory (LCRR inventory completion; 2026 LSL pilot; Green City Clean Waters exceeding 10-year reduction goal) and the federal architecture turbulence (LCRI defended by EPA in AWWA v. EPA; PFAS MCL administrative posture uncertainty; federal grant flow uncertainty). D6-Thread A operates at MILD-MODERATE intensity here.

Legal Architecture

Constitutional foundation

The Commerce Clause and Property Clause provide constitutional authority for federal water-quality regulation. The Supremacy Clause governs the cooperative-federalism relationship in which federal SDWA and CWA floors are implemented through state primacy programs and local utility operations. Under CWA cooperative federalism, PA has obtained EPA authorization to administer NPDES permitting within its borders; PA DEP administers NPDES with EPA Region 3 oversight. Statutory stability: HIGH; administrative vulnerability: LOW-MODERATE.

Federal statutory layer

Clean Water Act (CWA). 33 U.S.C. § 1251 et seq. Establishes the NPDES permitting program for point-source discharges to navigable waters (CWA § 402, 33 U.S.C. § 1342); regulates CSO discharges through EPA's 1994 CSO Control Policy and the Long-Term Control Plan framework (40 CFR Part 122 Subpart D); requires Phase I and Phase II MS4 stormwater permits for municipalities including Philadelphia (Phase I community; 40 CFR Part 122.26). CWA § 311 covers oil and hazardous-substance liability applicable to industrial discharges to the Schuylkill and Delaware River corridors. Statutory stability: HIGH; administrative vulnerability: MODERATE — NPDES enforcement priority and regional office capacity subject to EPA OECA emphasis changes (cross-reference SD1).

Safe Drinking Water Act (SDWA). 42 U.S.C. § 300f et seq. Governs National Primary Drinking Water Regulations (NPDWRs) for contaminants in public water systems. PA DEP Bureau of Safe Drinking Water (BSDW) holds EPA primacy for SDWA administration in PA, including oversight of PWD as the largest public water system in Pennsylvania (serving more than 1.5 million customers).

SDWA lead-in-water regulatory lineage.

Lead and Copper Rule (LCR, 1991). Foundational federal rule; action level 15 ppb at 90th percentile tap sample; established corrosion control treatment and partial LSL replacement triggers on exceedance.
Lead and Copper Rule Revisions (LCRR, 2021). Compliance date October 16, 2024. Required water systems to submit initial LSL inventories to state primacy agencies categorizing service lines as lead, galvanized requiring replacement (GRR), or unknown; Tier 1 public notification within 24 hours of action level exceedance; annual notification to customers served by lead, GRR, or unknown lines. Action level remains 15 ppb under LCRR.
Lead and Copper Rule Improvements (LCRI, 2024). Finalized October 8, 2024 (89 FR 86418); compliance date November 1, 2027 (baseline inventory plus service line replacement plan due to state primacy agency). Mandatory full LSL replacement within 10 years: all lead and GRR lines must be replaced by November 1, 2037 regardless of lead levels at the tap. Action level reduced to 10 ppb. Replacement plans must include prioritization strategy for schools, childcare facilities, and low-income neighborhoods; annual replacement reporting required; property-owner consent required for full-property-side replacement including the private-side line. Post-replacement: utilities must notify residents and provide certified lead-removing filters for up to six months. Statutory stability: HIGH (SDWA); administrative vulnerability: MODERATE — LCRI is confirmed operative under current EPA administration; EPA filed Respondents' Brief defending the rule in AWWA v. EPA (D.C. Circuit, February 20, 2026), arguing the rule "is lawful, reasonable, and should be upheld." No reconsideration or non-enforcement guidance initiated.

SDWA PFAS Maximum Contaminant Levels (MCLs). EPA finalized NPDWRs for six PFAS compounds in April 2024, including PFOA and PFOS at 4 parts per trillion (ppt) — among the most stringent drinking water standards ever promulgated under SDWA. Water systems required to complete initial PFAS monitoring by 2027; MCL compliance required by 2029. PWD's source waters (Schuylkill and Delaware Rivers) have documented upstream PFAS contamination from industrial and municipal sources; compliance feasibility depends on whether existing treatment processes achieve 4 ppt.

Federal agency layer

EPA Region 3. 1650 Arch Street, Philadelphia, PA 19103. Oversees CWA NPDES permits for PA facilities, including PWD's three water treatment plant discharges (Baxter, Queen Lane, Belmont) and its CSO program. EPA Region 3's 2012 Administrative Order for Compliance on Consent (AOCC) formally endorsed the Green City Clean Waters COA, integrating federal CWA oversight into the state-administered consent order framework.

EPA Office of Water. Administers the SDWA LCR regulatory lineage and PFAS NPDWRs. EPA's IIJA SDWA grant program provides federal infrastructure funding for LSL replacement; continuity of that grant stream under the current federal budget posture is subject to appropriations. EPA delayed releasing FY 2025 LSL replacement fund State Revolving Fund allocations (as of November 2025 per Unleaded Kids reporting), creating a capital-flow uncertainty dimension alongside the capital-gap finding.

State statutory and agency layer

Pennsylvania Safe Drinking Water Act (PA SDWA). 35 P.S. § 721.1 et seq. Establishes PA DEP primacy for federal drinking water regulation; incorporates federal NPDWRs by reference and authorizes PA DEP to establish additional state requirements. PA DEP BSDW receives and reviews PWD's LCRR inventory submission; will receive the LCRI baseline inventory and service line replacement plan; administers PFAS monitoring compliance schedule.

Pennsylvania Clean Streams Law. 35 P.S. § 691.1 et seq. Governs surface-water quality and authorizes PA DEP to administer the CWA NPDES program in Pennsylvania, issuing NPDES permits for point-source discharges to the Delaware River, Schuylkill River, Wissahickon Creek, Cobbs Creek, and their tributaries. The Clean Streams Law provides PA DEP authority over non-point-source runoff affecting drinking water source quality — including agricultural and industrial runoff from the Schuylkill River upper watershed. Regulations at 25 Pa. Code Chapters 91-102.

PA DEP Bureau of Safe Drinking Water (BSDW). Administers PA SDWA primacy including LCRR/LCRI oversight for all public water systems statewide.

PA DEP Bureau of Clean Water. Administers CWA NPDES permits for PA point sources with EPA Region 3 oversight. PA DEP is the COA counterparty for Green City Clean Waters (COA, June 1, 2011); receives PWD's periodic CSO status reports and 5-year performance standard compliance documentation.

Local statutory and agency layer

Philadelphia Home Rule Charter. Authorizes PWD to operate the City's water, wastewater, and stormwater systems as a City enterprise agency. The Philadelphia Code governs PWD's rate-setting structure: capital program rates are set through a rate case process subject to City Council and mayoral approval; the LCRI LSL replacement capital program — estimated at approaching half a billion dollars — is the largest scheduled capital compliance obligation PWD has faced.

Philadelphia Water Department (PWD). 1101 Market Street, Philadelphia, PA 19107. Provides drinking water to approximately 1.5 million regional customers from the Schuylkill and Delaware Rivers, treating water at the Baxter, Queen Lane, and Belmont plants. PWD holds CWA NPDES permits for treatment plant discharges; is the primary SDWA regulated party under PA DEP BSDW primacy; and manages the Green City Clean Waters COA compliance under the 2011 COA and 2012 EPA AOCC. PWD submits annual CSO compliance progress reports documenting GSI installations, impervious acreage managed, and equivalent mass capture against the 85% target. Administrative vulnerability: LOW-MODERATE — PWD capital program is rate-funded with IIJA supplement; IIJA funding continuity is subject to federal budget and infrastructure policy.

Cross-cutting structural features

Three structural features recur across the SD2 constituent profiles.

First, the substantive compliance trajectory under PA primacy. LCRR compliance achieved October 16, 2024; the 2026 LSL pilot (~1,000 replacements in North and West Philadelphia) is the operational entry point to the ~20,000-25,000 remaining LSL inventory; Green City Clean Waters has exceeded its 10-year reduction goal with nearly 3 billion gallons of stormwater runoff and sewer overflow kept out of local waterways since 2011 and green stormwater infrastructure managing more than 9,500 acres of impervious surface; PFAS compliance schedule operates toward the 2029 deadline.

Second, the rate-burden and capital-gap structure. The LCRI capital program approaches half a billion dollars; PWD's customer base is approximately 51% renters who cannot offset rate increases through homeowner tax deductions or receive the direct property-improvement benefit of LSL replacement. EPA delayed FY 2025 LSL replacement SRF allocations, adding a federal-funding-continuity uncertainty dimension.

Third, the owner-consent gap for renters. LCRI requires property-owner authorization for the full-property-side replacement including the private-side line. In multi-family rental buildings — the dominant housing type in PA-3's highest-LSL sub-areas — the tenant with the most direct health interest in replacement cannot independently authorize it; the property owner determines the timeline.

Constituent profiles

These profiles illustrate the structural features above. Drawn from the verified LCRI rule (89 FR 86418), the EPA April 2024 PFAS MCLs, and PWD's published Green City Clean Waters progress applied to documented PA-3 conditions.

Profile 1: North Philadelphia renter on a block within the 2026 LSL pilot priority zone

Constituent type: a PA-3 constituent renting in a pre-1940 row house in Strawberry Mansion or Cecil B. Moore whose service line has been inventoried as lead and whose block is within the 2026 pilot priority zone. North/Northwest Philadelphia Core sub-area.

Pathway through the institutional system. Following LCRR compliance (October 16, 2024), PWD submitted its initial LSL inventory to PA DEP BSDW. Affected customers received LCRR notification within 30 days; PWD offers free water testing upon request; pilot LSL replacement requires property-owner authorization for full-property-side replacement; post-replacement filters provided for up to six months. The constituent's pathway depends on landlord responsiveness — not on the tenant's health interest or urgency.

Outcome. The structural asymmetry is the load-bearing finding for this profile: the regulatory mandate runs to PWD (must offer replacement) and to the property owner (must consent); the tenant who lives in the building and whose water passes through the lead line is the party with the most direct health interest and the least direct agency in the replacement timeline. Until replacement occurs — whether in the 2026 pilot wave or a later wave — the protective measure is a flushing-and-filtering protocol assigned to the household. A resident on a pilot-priority block who receives replacement during the 2026 wave gets the structural remediation; a resident in the same sub-area on a non-pilot block faces the flushing-and-filtering protocol for potentially up to 11 years (2037 mandatory deadline). The gap between these two outcomes is a function of pilot sequencing and falls most heavily on renters who cannot influence the consent process.

Profile 2: South Philadelphia constituent adjacent to a CSO outfall

Constituent type: a PA-3 constituent in Point Breeze or Grays Ferry living near the Delaware River or a local tributary that receives CSO discharges during storm events. South/Southwest sub-area.

Pathway through the institutional system. The constituent's pathway is involuntary and not individually triggered. Green City Clean Waters CSO reduction program operates under the 2011 COA (85% reduction target by 2036); NPDES permit conditions require PWD to notify the public of CSO occurrences that may affect recreational use of receiving waters; real-time notification to residential neighbors of outfalls not specifically associated with recreational water is not required.

Outcome. The constituent receives reduced overflow frequency relative to pre-2011 baseline — a documented substantive improvement — but continued overflow events during intense rainfall. At the documented 164 CSO outfall count, the density of permitted overflow points in South and West Philadelphia creates structurally higher exposure frequency per land area than in areas of the city served by separate storm and sanitary sewers. Green City Clean Waters reduces overflow volume per event; it does not eliminate overflow events. The Both/And at SD2 is expressed most concretely at this profile.

Profile 3: West Philadelphia household with an unconfirmed-unknown service line material status

Constituent type: a PA-3 constituent in Mantua or Mill Creek whose LCRR inventory categorized their service line as "unknown" — the material could not be confirmed from historical records alone. West Philadelphia Core sub-area.

Pathway through the institutional system. Unknown service lines are treated as potentially lead-containing: LCRI requires characterization by the 2027 baseline inventory and replacement if confirmed as lead or GRR by 2037. The constituent receives LCRR annual notification of unknown material status and health information; PWD is obligated to characterize unknown lines through field inspection, predictive modeling, or excavation as part of the LCRI baseline inventory; LCRI filters distributed to customers with unknown-status lines pending material confirmation.

Outcome. The constituent receives ongoing material uncertainty and a precautionary recommendation to treat the water as if the line contains lead — flushing before first use; filtering for drinking and cooking — until the line is characterized and, if confirmed as lead, replaced. The "unknown" category is not a regulatory failure — it reflects the limits of historical infrastructure documentation in a city built across multiple centuries of pipe-material technology. What it produces for this constituent is a structural exposure uncertainty that the LCRI acknowledges (by requiring characterization) but cannot immediately resolve.

Conversational note

Philadelphia's water story since 2011 is one of the country's more ambitious infrastructure compliance commitments. Green City, Clean Waters pioneered green stormwater infrastructure as the primary CSO compliance strategy when nearly every comparable city opted for the conventional gray-infrastructure approach — expensive underground tunnels rather than trees, rain gardens, and permeable pavement. The fact that PWD exceeded its 10-year reduction goal — keeping nearly 3 billion gallons of combined sewer overflow out of local waterways — is a substantive regulatory achievement, and it is the correct starting point for SD2's Both/And: the functioning side of this sub-domain is real and documented.

The lead service line picture is more complicated, and the complication is structural rather than motivational. Philadelphia has somewhere between 20,000 and 25,000 lead service lines — a legacy of a city built largely before the 1986 SDWA ban on lead pipes — and replacing them all is a 10-to-11-year, multi-billion-dollar undertaking that dwarfs the 2026 pilot. The pilot (~1,000 lines in North and West Philadelphia) is where the regulatory architecture meets constituent reality most acutely: these are the neighborhoods with the highest pre-1940 housing density, the highest renter percentages, and the most limited household capacity to respond to lead exposure alerts. Federal LCRI rules require replacement and provide a framework for prioritization; they do not provide the capital, which comes from water rates, state infrastructure funds, and IIJA federal aid. The fiscal-regulatory interdependency is load-bearing: the mandate without adequate capital flow produces a replacement program that is legally compliant in its timeline but slow relative to constituent exposure need. And the owner-consent barrier — the structural asymmetry by which a tenant's exposure is remediated on the landlord's schedule, not the tenant's — sits at the center of the access gap for renters.

The PFAS dimension adds a third register to SD2's Both/And. PWD draws from the Schuylkill and Delaware Rivers, which carry documented upstream PFAS contamination. Whether PWD's existing treatment achieves the April 2024 PFAS MCLs (4 ppt for PFOA/PFOS; compliance deadline 2029) requires monitoring data not yet publicly confirmed at this drafting. The federal-turbulence overlay here is specific: the current EPA administration has shown less regulatory enthusiasm for the PFAS MCLs than the administration that finalized them, creating uncertainty about whether the compliance timeline will be enforced as promulgated. That uncertainty is the MILD-MODERATE D6-Thread A expressed at SD2: the local utility's operational posture is oriented toward compliance; the federal regulatory environment in which it is operating is less stable than the local posture suggests.

Geography & representation

Data provenance. SDWA architecture (42 U.S.C. § 300f et seq.); LCR (1991), LCRR (2021, October 16, 2024 compliance date), and LCRI (89 FR 86418 finalized October 8, 2024; November 1, 2027 baseline; November 1, 2037 mandatory full replacement) are documented in the Federal Register. EPA April 2024 PFAS MCLs (PFOA/PFOS at 4 ppt; six PFAS compounds total; 2027 monitoring; 2029 compliance) are documented in the Federal Register. PWD's October 16, 2024 LCRR initial inventory submission and 2026 LSL pilot architecture are documented at water.phila.gov. The Green City Clean Waters 2011 COA, 2012 EPA AOCC, 85% reduction target by 2036, and the nearly 3 billion gallons / 9,500+ acres of impervious surface managed since 2011 figures are documented at water.phila.gov. EPA's Respondents' Brief defending LCRI in AWWA v. EPA (D.C. Circuit, February 20, 2026) is documented in the D.C. Circuit docket and CDM Smith LCRI updates (December 2026). EPA's delayed release of FY 2025 LSL replacement SRF allocations is documented per Unleaded Kids reporting (November 2025). PA SDWA, PA Clean Streams Law, and PA DEP BSDW / Bureau of Clean Water architecture are documented in PA primary sources. PWD treatment plant geography (Baxter, Queen Lane, Belmont) and 164 CSO outfalls are documented in PWD publications. PA-3-specific LSL inventory figures, PFAS source-water characterization, and unknown-line characterization methodology are flagged for institutional retrieval at PWD water quality reports and PA DEP BSDW records.

PA-3 statistical profile. PWD's LCRR initial inventory (submitted October 2024) is the baseline for LCRI compliance planning. The estimated stock of lead and GRR service lines in Philadelphia — between 20,000 and 25,000 — requires institutional retrieval of the submitted inventory figure. The 2026 pilot replacing approximately 1,000 LSLs represents roughly 4-5% of the estimated total. To achieve 100% replacement by November 2037 from a 2027 baseline, PWD must sustain approximately 2,000-2,500 replacements per year — a pace roughly 2x the 2026 pilot. PWD serves approximately 1.5 million regional customers from the Schuylkill and Delaware Rivers via three treatment plants. Philadelphia's customer base is approximately 51% renters per ACS. Green City Clean Waters has kept nearly 3 billion gallons of combined sewer overflow out of local waterways since 2011 with green stormwater infrastructure managing more than 9,500 acres of impervious surface. 164 CSO outfalls under the COA architecture.

Geographic variation.

North/Northwest Philadelphia Core (Strawberry Mansion, Nicetown, Cecil B. Moore). Highest concentration of pre-1940 housing stock in PA-3; correspondingly highest LSL prevalence; 2026 pilot prioritizes this sub-area. High renter proportion with significant small-landlord multi-family building stock — the owner-consent barrier is most acute where landlords are least institutionally equipped to navigate PWD replacement outreach.
West Philadelphia Core (Mantua, Mill Creek, University City, West Powelton). Pre-1940 housing stock dominant; LSL pilot covers this sub-area. University-adjacent rental market means tenant populations are transient, reducing the likelihood that any given tenant is present through the full notification-to-replacement cycle. Anchor-institution facilities (Penn / Penn Medicine, Drexel) connect to PWD's combined sewer system; their stormwater and sanitary flows contribute to CSO volume during wet-weather events.
Northwest Philadelphia (Germantown, Roxborough, Manayunk). Housing vintage is more varied; LSL prevalence lower than the Core sub-areas but not zero. Wissahickon Creek corridor is the primary surface-water quality concern; CSO outfall density lower.
South/Southwest Philadelphia (Grays Ferry, Point Breeze, South Philadelphia). Extensive pre-1940 rowhouse stock in Point Breeze and Grays Ferry; Delaware River CSO outfalls concentrated at the southern end; Lower Schuylkill river contamination from the industrial corridor affects surface-water quality at the South/Southwest boundary zone.

LSL prevalence at sub-area level, PFAS finished-water concentrations, and PWD LCRI capital plan adequacy require institutional retrieval.

Gap analysis

Four structural gaps recur across the constituent profiles and the architectural layers above.

G6-SD2-01 — LCRI compliance capital gap: rate burden and low-income constituent distribution [SD] MEDIUM (MC-06 verification update). The LCRI's mandatory 10-year LSL replacement mandate requires PWD to fund a capital program approaching half a billion dollars — primarily through water rates — for a system serving a customer base including approximately 51% renters. Rate increases for LSL replacement fall on all ratepayers; low-income renters cannot offset the cost through homeowner tax deductions and do not receive the direct property benefit of LSL replacement. The LCRI mandate is confirmed operative under current EPA administration; EPA filed Respondents' Brief defending the rule in AWWA v. EPA (D.C. Circuit, February 20, 2026), arguing it "is lawful, reasonable, and should be upheld." No reconsideration or non-enforcement guidance initiated; oral argument before D.C. Circuit likely later in 2026. EPA delayed releasing FY 2025 LSL replacement SRF allocations (as of November 2025 per Unleaded Kids reporting), creating a capital-flow uncertainty dimension. Representation implication: Low-income renters in North and West Philadelphia — the sub-areas with the highest LSL burden and the 2026 pilot priority — bear the rate impact of a capital program they do not control the pace of, while continued lead exposure during the pre-replacement period remains a structural risk that the regulatory architecture has not yet eliminated.

G6-SD2-02 — Owner-consent barrier: structural access gap for renters in LSL replacement [SD] MEDIUM-HIGH. LCRI requires property-owner authorization for full-property-side LSL replacement. In multi-family rental buildings — the dominant housing type in PA-3's highest-LSL sub-areas — the tenant with the most direct health interest in replacement cannot independently authorize it; the property owner determines the timeline. A landlord who is unresponsive to PWD outreach or unwilling to permit access can delay replacement beyond the pilot window, leaving tenants with the flushing-and-filtering protocol as their sole interim protection. Representation implication: The owner-consent barrier produces a structural asymmetry in which renter health interest is mediated by landlord cooperation. This gap falls specifically on renters, who are disproportionately represented in PA-3's highest-LSL neighborhoods and who have the least institutional leverage to accelerate their landlord's responsiveness.

G6-SD2-03 — PFAS compliance gap: treatment infrastructure uncertainty [SD] MEDIUM. EPA's April 2024 PFAS MCLs (PFOA/PFOS at 4 ppt; compliance deadline 2029) require PWD to verify compliance and potentially upgrade treatment infrastructure. Philadelphia's Schuylkill and Delaware River source waters have documented upstream PFAS contamination. Whether existing treatment achieves the 4 ppt standard is not publicly confirmed at this drafting. PFAS MCLs have been contested by water utility associations; current EPA posture toward enforcement and potential reconsideration is uncertain. Representation implication: PA-3 constituents depend on PWD's PFAS treatment compliance on a timeline that requires capital planning under regulatory uncertainty about the current EPA administration's enforcement posture. The PFAS pathway is entirely passive from the constituent's perspective: no individual notification, no individual protective action, no individual complaint mechanism.

G6-SD2-04 — CSO post-2036 gap: climate-intensification stress on consent order design [SD] MEDIUM. The 2011 COA and Green City Clean Waters were designed against a pre-2011 precipitation baseline. Climate change is intensifying rainfall events in the Philadelphia region, increasing the overflow volume that GSI must manage to achieve equivalent mass capture. The 85% reduction target calibrated to historical precipitation may require more GSI investment than the original plan assumed to achieve equivalent water quality outcomes under an intensified precipitation future. Representation implication: PA-3 constituents in South and West Philadelphia — near the highest CSO outfall density — face a compliance architecture whose 2036 target was calibrated to a precipitation baseline that is shifting, creating a prospective gap between the plan's design and the outcomes it will produce under documented climate change.

D6-Thread A at SD2 — MILD-MODERATE intensity. Federal CWA/SDWA architecture is under turbulence (EPA enforcement-emphasis changes; PFAS MCL administrative posture uncertainty; federal grant flow uncertainty including the delayed FY 2025 LSL SRF allocations) while PWD compliance trajectory continues on its own schedule under the state consent order. The divergence is less dramatic than at SD1 (GHG rescission) or SD5 (EJ rollback vs. state expansion) but real.

Where this leads

Federal House representation operates at SD2 through CWA/SDWA appropriation advocacy (IIJA SDWA LSL funding continuity; PFAS treatment funding; CWA NPDES program adequacy), federal regulatory-policy engagement (LCRI enforcement posture in AWWA v. EPA; PFAS MCL reconsideration trajectory; CSO Long-Term Control Plan policy), and federal-state coordination on PA DEP BSDW primacy. PA-state-level engagement at PA DEP BSDW appropriations (FY 2026-27 budget pending) and Bureau of Clean Water is the principal complementary locus. Local Philadelphia engagement at PWD rate-setting, City Council capital-program approval, and Philadelphia Water Rate Board operates at the third layer.

The next sub-domain — Land and Site Remediation Architecture — analyzes PA Act 2 of 1995 voluntary cleanup, the 3 active NPL sites in Philadelphia County (Enterprise Avenue, Metal Bank, Lower Darby Creek), and the brownfield-redevelopment-pace HOM with 5 mechanisms.