I need to stay up-to-date on EPA regulations. What are the best resources for an environmental engineer?

For an environmental engineer, the best approach is to combine primary regulatory sources (to know what is legally changing) with technical interpretation sources (to understand implementation). These are the resources I’d prioritize:

1. EPA’s official regulations hub (start here)

Use it for:

• Current regulations by topic (air, water, waste, chemicals, cleanup, etc.)
• Compliance guidance
• Links to major environmental statutes: - Clean Air Act
• Clean Water Act
• RCRA
• CERCLA/Superfund
• TSCA
• FIFRA

EPA also provides regulatory information organized by topic and sector, which is useful for engineers working in specific industries.

2. 40 CFR (your regulatory “source of truth”)

Most EPA requirements end up in Title 40 of the Code of Federal Regulations (40 CFR). Key areas include:

• Air: 40 CFR Parts 50–99 (NAAQS, NSPS, NESHAP/MACT, permitting requirements)
• Water: 40 CFR Parts 100–149 (CWA programs, wastewater, drinking water)
• Hazardous waste: 40 CFR Parts 260–279 (RCRA)
• Toxic substances: 40 CFR Parts 700–799 (TSCA)

The eCFR is especially useful because it is updated continuously, unlike the printed CFR volumes.

3. Federal Register alerts (catch changes before they become law)

Environmental engineers should monitor:

• Proposed rules
• Final rules
• Notices
• Comment periods

The Federal Register is where proposed and final federal regulations are announced before they are incorporated into the CFR.

4. Regulations.gov (track and comment on rules)

Useful for:

• EPA rulemaking dockets
• Technical supporting documents
• Regulatory impact analyses
• Public comments
• Proposed rule history

EPA identifies Regulations.gov as the official online system for accessing and commenting on rulemaking materials.

5. EPA regulatory agendas (see what is coming)

Good for strategic planning because it shows:

• Rules under development
• Anticipated regulatory actions
• Agency priorities

EPA publishes these agendas twice yearly.

6. EPA newsletters and email alerts

Set up subscriptions for the EPA offices most relevant to your work:

7. Professional organizations (for interpretation and practice)

These are valuable because they translate regulations into engineering practice:

• Air & Waste Management Association — strong for air permitting, emissions, waste, and compliance topics.
• Water Environment Federation — useful for wastewater and water regulations.
• American Water Works Association — useful for drinking water standards and utility practice.
• National Association of Environmental Professionals — broader environmental compliance and NEPA-related topics.

8. Regulatory intelligence services (for compliance-heavy roles)

If your job involves permitting, audits, or corporate compliance, consider paid tools such as:

These can save time by summarizing changes, but they should supplement—not replace—primary EPA sources.

A practical weekly routine

For many environmental engineers, a 30–60 minute weekly review works well:

1. Check EPA alerts relevant to your media (air/water/waste).
2. Review Federal Register or EPA rulemaking updates.
3. Scan Regulations.gov for proposed rules affecting your industry.
4. Verify important changes against 40 CFR.
5. Save interpretations, guidance memos, and enforcement examples relevant to your facility.

If you tell me your specialty (air permitting, wastewater, hazardous waste, remediation, EHS, consulting, government, etc.), I can narrow this to the highest-value sources and subscriptions for that role.

Staying on top of EPA regulations requires a mix of primary government sources, daily regulatory trackers, and professional networks.

Official & Primary Sources

• EPA Newsroom : The direct feed for official press releases, major policy announcements, and newly proposed or finalized rules straight from the agency.
• Federal Register : The daily journal of the U.S. government where all official EPA proposed rules, final rules, and notices are legally published. You can set up custom email alerts by topic (e.g., Clean Air Act, RCRA).
• EPA Laws and Regulations : A comprehensive hub detailing the underlying statutes, executive orders, and federal regulations governing environmental compliance.
• EPA Compliance Assistance : Great for operational guidance documents broken down by media type (air, water, land, and cross-cutting issues).

Compliance Data & Tracking Tools

• Enforcement and Compliance History Online (ECHO) : Essential for assessing enforcement trends, checking facility-specific compliance records, and seeing how regulations are actively applied in practice.
• GovInfo : Managed by the U.S. Government Publishing Office, providing authenticated, searchable access to official federal publications and regulatory text.

If you want to narrow this down, let me know:

• Which specific media do you focus on most (e.g., Air/CAA, Water/CWA, Waste/RCRA)?
• Do you prefer free government feeds or are you looking for paid professional subscription services (like Bloomberg Environment or curating tools)?

If you're an environmental engineer, I’d use a layered approach: primary legal sources for what actually changed, EPA sources for interpretation and implementation, and a few professional sources for context.

Best resources

1. epa.gov — Start here. It organizes regulations by statute, topic, sector, compliance, enforcement, and guidance. EPA currently notes that regulations are codified primarily in Title 40 CFR.
2. ecfr.gov — Your best source for the current regulatory text. Use it when you need to know what the requirement actually says rather than what an EPA summary says.
3. federalregister.gov — Essential for tracking proposed rules, final rules, effective dates, notices, and EPA's explanations of regulatory changes. EPA specifically distinguishes the Federal Register, which announces regulatory actions, from the CFR, where final requirements are codified.
4. regulations.gov — Particularly valuable for engineers because you can get into the docket: proposed rule, technical support documents, economic analyses, comments, responses to comments, and supporting studies. EPA identifies it as its official online system for commenting on rulemakings.
5. epa.gov — Use this to see what EPA is working on before it becomes a final rule. EPA's agenda is updated twice a year; the current 2026 agenda is available through RegInfo.
6. reginfo.gov — Excellent for forward-looking regulatory intelligence. Search for EPA and follow individual RINs (Regulation Identifiers) to see where rulemakings are headed. The current site contains the 2026 Regulatory Plan and Unified Agenda.
7. EPA topic-specific regulatory pages — These are especially useful once you know your specialty. EPA maintains dedicated regulatory information for air, water, RCRA/waste, chemicals/TSCA, pesticides, Superfund, PFAS, etc.

• Air/CAA → NAAQS, NSR/PSD, Title V, MACT/NESHAP, GHG
• Water/CWA → NPDES, effluent guidelines, pretreatment, wetlands
• Waste/RCRA → hazardous waste, generator rules, corrective action
• Chemicals/TSCA → chemical restrictions and reporting
• CERCLA → hazardous substances and cleanup requirements
• Drinking water/SDWA → MCLs and monitoring requirements

For an engineer, I'd add these

EPA ECHO is very useful when your work involves facility compliance. It lets you investigate inspections, violations, enforcement and compliance histories rather than merely reading the regulations.

Your state environmental agency is equally important. EPA regulations often establish the federal baseline, but your permit and day-to-day compliance obligations may come from an authorized state program. EPA provides links to state environmental regulatory information.

For professional interpretation, I'd also consider American Society of Civil Engineers, Air & Waste Management Association, and American Water Works Association depending on your specialty. These can be useful for technical interpretation and industry context, but I would always verify the underlying requirement against the Federal Register/CFR.

A practical monitoring workflow

For staying current without drowning in regulatory emails, I'd set up:

Daily/near-daily: Federal Register alerts for EPA + your major statutes/topics.

Weekly: EPA news/regulatory updates + review of important Regulations.gov dockets.

Monthly: Check the relevant EPA program pages and your state agency's announcements.

Quarterly: Review the Unified Agenda for rulemakings that could affect your facilities/projects.

When something matters: Go from EPA summary → Federal Register → docket/supporting documents → eCFR → applicable state rule/permit.

That's particularly important right now: EPA's regulatory landscape is changing rapidly in 2026, including both deregulatory actions and active rulemakings. For example, EPA's current materials describe a major deregulatory initiative, while individual programs such as New Source Review continue to have active proposed rulemakings.

If you tell me your specialty (air, water, hazardous waste, environmental permitting, remediation, EHS, etc.) and industry, I can narrow this down to a 10-resource monitoring stack with the specific EPA pages, email alerts, newsletters, and regulations you should follow.

Staying ahead of EPA regulations requires a mix of primary government sources, regulatory tracking clearinghouses, and professional updates.

Official & Primary Government Resources

• Regulations.gov : The official federal portal where you can search dockets, read proposed rules, and submit formal public comments. You can set up saved searches or alerts for specific environmental topics.
• Federal Register : The daily journal of the U.S. government where all new EPA final rules, proposed rules, and notices are officially published.
• EPA Laws and Regulations Page : The main portal for tracking active rulemakings, compliance guidance, and enforcement priorities.
• GovInfo : Maintained by the U.S. Government Publishing Office, it gives you authenticated access to historical and current federal regulations, bills, and the Code of Federal Regulations (CFR).

Compliance & Navigation Tools

• EPA Compliance Assistance Centers : Industry-specific tools and contact advisors designed to help regulated entities figure out specific environmental obligations under the Clean Air Act (CAA), Clean Water Act (CWA), Resource Conservation and Recovery Act (RCRA), and more.
• EPA Regulation Navigation Tools : Interactive, online guidance tools specifically helpful for stationary sources and complex air quality subparts.

Professional Networks & Newsletters

• A&WMA (Air & Waste Management Association) : Excellent for technical updates, webinars, and peer networking regarding air, waste, and environmental management changes.
• WEF (Water Environment Federation) or AWWA : Essential if your focus is water/wastewater regulations under the CWA and Safe Drinking Water Act (SDWA).
• LexisNexis / Bloomberg Environment / Enhesa : Premium subscription services if you need automated, legal-grade compliance tracking and deep-dive analysis on how new rules impact engineering designs or facility operations.

To help me narrow this down, could you tell me which specific environmental media you work with most (e.g., air emissions, wastewater/stormwater, hazardous waste/RCRA, or remediation), or if you prefer free public tools versus paid corporate compliance software?

For an environmental engineer, I’d use a primary-source stack rather than relying on newsletters alone. The most useful resources are:

1. EPA Laws & Regulations — your starting point

   • Central hub for the Clean Air Act, Clean Water Act, RCRA, CERCLA, TSCA, FIFRA, drinking water, PFAS, compliance, enforcement, and guidance.
   • EPA also organizes material by regulated topic and industry sector.

2. eCFR / Title 40 CFR — the actual regulatory text

   • Keep this bookmarked.
   • 40 CFR contains most federal environmental regulations. EPA specifically recommends the e-CFR as the up-to-date online version.
   • Particularly important parts depend on your work: air (Parts 50–99), water (100–149), hazardous waste (240–282), pesticides (150–189), and hazardous substances/chemicals (700+).

3. Federal Register — proposed and final rules

   • This is where you see proposed rules, final rules, notices, effective dates, compliance dates, and agency explanations.
   • A useful mental model: Federal Register = what's changing; CFR = what's currently codified. EPA itself makes this distinction.

4. Regulations.gov — dockets and supporting material

   • Extremely valuable for engineers because you can get the technical supporting documents, regulatory impact analyses, comments, and EPA responses, not just the regulatory language.
   • EPA identifies Regulations.gov as its official online commenting system and rulemaking clearinghouse.

5. EPA Regulatory Agendas & Plans — what's coming next

   • The Semiannual Regulatory Agenda is particularly useful for anticipating rules before they become final.
   • EPA publishes the agenda twice a year and its Regulatory Plan identifies higher-priority regulatory actions.

6. EPA Compliance & Enforcement — learn what EPA actually cares about

   • Useful for understanding inspection priorities, enforcement trends, settlements, and practical compliance expectations.
   • This can be more informative than simply reading regulations because it shows where facilities are getting into trouble.

7. EPA Enforcement and Compliance History Online (ECHO) — facility-level intelligence

   • Particularly useful if you do permitting, due diligence, audits, compliance assessments, or consulting.
   • You can investigate permits, inspections, violations, enforcement actions, and facility compliance histories.

I'd also add state-level resources

For an engineer practicing in Texas, federal EPA rules are only half the picture. Texas environmental requirements can be more directly relevant to permitting and day-to-day compliance.

The Texas Commission on Environmental Quality (TCEQ) should therefore be in your regular rotation, particularly for air permits, water permits, waste, remediation, and environmental reporting.

A practical monitoring routine

If you want to stay current without spending hours every day, I'd do:

Daily/near-daily

• Federal Register alerts for your specific CFR parts/topics
• EPA news and regulatory announcements

Weekly

• Regulations.gov searches for your major regulatory topics
• EPA enforcement/compliance developments
• State agency updates

Monthly

• Review significant proposed/final rules
• Check upcoming effective/compliance dates
• Update your internal regulatory matrix

For major rules

1. Read the Federal Register notice.
2. Pull the Regulations.gov docket.
3. Read EPA's fact sheet/supporting technical documents.
4. Check the e-CFR once finalized/effective.
5. Check your state implementation requirements.
6. Record effective date, compliance date, applicability, monitoring, reporting, and recordkeeping requirements.

That workflow is much more reliable than depending on an industry newsletter to tell you what changed. EPA's own description of the regulatory process follows essentially this progression: proposal → comments/docket → final rule → codification in the CFR.

One current example of why this matters: EPA's regulatory landscape is actively changing in 2026. For example, EPA published a proposed revision to its Risk Management Program in February 2026, while its PFAS drinking-water regulatory position has also been evolving.

If you tell me whether your work is primarily air, water/wastewater, hazardous waste, remediation, industrial EHS, or environmental consulting, I can narrow this down to a 10-resource "must monitor" stack, including the specific CFR parts, EPA newsletters/alerts, and Texas resources most relevant to you.

Staying on top of EPA regulations requires a mix of primary government feeds, tracking tools, and professional networks. The most effective resources for an environmental engineer are organized below by category.

Direct EPA Tracking Tools & Portals

• Regulations.gov : The official federal hub where you can search proposed and final rules, access public dockets, and submit comments on upcoming EPA rulemakings.
• EPA Laws & Regulations Page : Provides direct access to the Unified Agenda of Federal Regulatory and Deregulatory Actions, letting you see rules currently under development.
• Enforcement and Compliance History Online (ECHO) : Essential for checking compliance data, enforcement cases, and pollutant trends across over 800,000 regulated facilities.
• EPA Newsroom Subscriptions : Allows you to sign up for targeted email listservs filtered by specific media topics (Air, Water, Waste) or individual EPA regional offices.

Professional & Multi-Agency Platforms

• FedCenter : A comprehensive environmental compliance and-stewardship assistance platform tailored for federal facilities, but packed with cross-agency regulatory guidance applicable to private sector engineering as well.
• State Environmental Agencies : Because many federal programs (like the Clean Water Act's NPDES permits) are delegated to state departments of environmental protection, regularly checking your specific state's environmental portal is vital for localized and immediate changes.
• Professional Societies : Organizations like the Water Environment Federation (WEF), Air & Waste Management Association (A&MA) , and the American Society of Civil Engineers (ASCE) offer member newsletters, technical committees, and policy trackers that break down complex regulatory shifts into engineering realities.

To help narrow this down, what specific media or industry sector (e.g., Clean Air Act/air permitting, RCRA/hazardous waste, or Clean Water/NPDES) do you primarily work in? I can tailor a more specific list of resources or alerts for your focus area.

Staying current on EPA regulations requires a mix of primary government sources, regulatory tracking aggregators, and professional networks.

Official Government & Primary Sources

• Federal Register : The daily journal of the U.S. government. You can set up custom topic alerts (e.g., specific to the Clean Air Act or RCRA) to get notified the exact day a proposed rule, final rule, or notice is published.
• Regulations.gov : The official hub for tracking federal rulemakings, reading public comments, and reviewing supporting docket materials.
• US EPA Laws and Regulations Hub : The primary landing page for direct guidance on environmental statutes, executive orders, and agency-wide regulatory policies.
• EPA Enforcement and Compliance History Online (ECHO) : Excellent for monitoring compliance data trends, enforcement priorities, and specific facility actions.

Academic & Legal Trackers

• Harvard Environmental and Energy Law Program (EELP) Regulatory Tracker : Provides clear, objective breakdowns and timelines of major shifting EPA rules, rollbacks, and updates.
• FedCenter : A collaborative compliance assistance platform sponsored by the EPA and other federal entities that offers comprehensive federal environmental program guidance and tools.

Training & Professional Development

• EPA Tools and Resources Training Webinar Series : Monthly public webinars hosted by the EPA to translate recent agency research, models, and practical compliance frameworks [1.1.2.
• Industry Associations : Joining sector-specific groups (such as WEF for water/wastewater or AWMA for air and waste management) provides peer-reviewed interpretations of how new rules hit the ground practically.

To help narrow this down, what specific media or sector (such as Clean Air Act air permits, NPDES water discharges, or RCRA hazardous waste) do you primarily work with? I can point you toward niche technical guidance lists for that discipline.

If you’re an environmental engineer, I’d use a layered system rather than relying on one newsletter. The key is to distinguish what is legally in force, what EPA is proposing, and what it means operationally.

My recommended stack

1. EPA Laws & Regulations — your starting point

   • EPA’s central portal for regulations, compliance, enforcement, guidance, and state regulatory information.
   • Especially useful for jumping into regulations by environmental topic or industry.

2. [eCFR — Title 40](https://www.ecfr.gov/current/title-40 — the actual requirements - Title 40 contains the federal environmental regulations. - Use the eCFR when you need to determine what the current regulatory text actually says. EPA itself points users to the eCFR as the up-to-date online version of 40 CFR. cite?utm_source=chatgpt.com)

   • This should be your final stop when answering questions like "Are we required to do X?"

3. Federal Register — what is changing

   • This is where proposed rules, final rules, notices, and effective dates appear.
   • Particularly important because a proposed rule isn't the same thing as an enforceable requirement. EPA describes the Federal Register as the official daily publication for federal rules, proposed rules, and notices.

4. Regulations.gov — the rulemaking docket

   • Search by docket number and you'll find the proposed rule, supporting documents, technical material, comments, and other docket information.
   • This is invaluable when you're trying to understand why EPA is changing a requirement, not just what the proposed regulatory text says. EPA calls it its official online commenting system and rulemaking clearinghouse.

5. EPA Regulatory Agenda — what's coming

   • The Unified/Semiannual Regulatory Agenda is excellent for seeing EPA's planned rulemakings before they become final rules.
   • I would review this at least quarterly if regulatory planning is part of your job.

6. EPA's environmental-topic pages

   • Depending on your specialty, follow the EPA pages for Clean Air Act, Clean Water Act/NPDES, RCRA, CERCLA, EPCRA, TSCA, FIFRA, SDWA, and NEPA.
   • EPA maintains summaries of these statutes and their regulatory frameworks.

Don't overlook state regulations

For an environmental engineer doing actual compliance work, federal EPA rules are only half the picture. Many federal programs are administered by state environmental agencies, and state requirements can be more stringent. EPA specifically provides state/regional regulatory information for this reason.

I'd therefore bookmark your state's environmental agency alongside EPA and monitor:

• permits and permit modifications
• state implementation plans
• state water-quality standards
• hazardous-waste requirements
• enforcement announcements
• proposed legislation/rules
• agency guidance and policies

For interpretation rather than primary authority

I'd supplement the government sources with a good environmental-law/regulatory newsletter. These are useful for quickly spotting important developments, court decisions, and practical implications before you have time to read a 300-page rulemaking.

That's particularly valuable right now: environmental regulation is moving quickly in 2026, with active EPA rulemakings and significant litigation affecting the scope of EPA authority.

One important rule: don't treat a consultant, law firm, trade association, or newsletter summary as the authority. Use it to find the development, then verify the requirement in the Federal Register, eCFR, permit, statute, or applicable state regulation.

A practical workflow I'd recommend

Daily/weekly:
Federal Register + EPA alerts/news → identify changes.

Weekly:
Regulations.gov → inspect important dockets and supporting documents.

Monthly:
Your state environmental agency → check state-specific developments.

Quarterly:
EPA Regulatory Agenda → identify things that could affect projects, permits, or compliance programs.

When making a compliance decision:
Federal Register/eCFR + permit + state regulation + applicable guidance → document your conclusion.

If you tell me your area of practice (air, water, hazardous waste, remediation, industrial EHS, environmental permitting, etc.), I can narrow this down to a 10-resource "must follow" list and include the most useful EPA newsletters/alerts and professional sources for that specialty.

Staying ahead of EPA regulations requires a mix of primary government feeds, active tracking tools, and professional networks.

Official EPA and Federal Resources

• Regulations.gov : The official online clearinghouse where you can search for active EPA dockets, read proposed and final rules, and submit public comments during rulemaking phases.
• EPA Laws & Regulations Hub : Provides direct access to the Unified Agenda of Federal Regulatory and Deregulatory Actions, agency policy statements, and guidance documents.
• The Federal Register : The daily journal of the U.S. government. Setting up a customized alert for "Environmental Protection Agency" here ensures you see rules the morning they are officially published.
• RCRA Online : An indispensable database if you work in waste management or remediation, indexing historical and current EPA interpretations of Resource Conservation and Recovery Act (RCRA) regulations.
• Enforcement and Compliance History Online (ECHO) : Excellent for tracking compliance metrics, enforcement data, and national enforcement initiatives across regulated sectors.

Specialized Trackers and Aggregators

• Legal and Academic Trackers : University-backed programs like the Harvard Environmental & Energy Law Program (EELP) publish granular, engineering-relevant trackers breaking down complex rule changes on air, water, and chemicals.
• Third-Party Monitoring Tools : Platforms like PageCrawl.io EPA Monitoring or customized RSS feeds targeting specific EPA newsroom sub-pages can automate the grunt work of checking for updates.

Professional and State-Level Channels

• State Environmental Agencies : Federal rules often trigger state-level implementation updates. Regularly check your specific state’s Department of Environmental Protection (e.g., TCEQ, MassDEP, or equivalent) because local permit limits and timelines can be stricter than federal baselines.
• Industry Associations : Joining sector-specific groups (such as WEF for water/wastewater or AWMA for air & waste management) provides access to member-only regulatory digests and committee interpretations that explain how rules apply practically in the field.

To narrow this down, what specific media program or industry sector (e.g., Clean Air Act/air permitting, Clean Water Act/NPDES, or RCRA/hazardous waste) do you primarily work with? I can recommend more targeted resources or specific compliance listservs.

If you’re an environmental engineer, I’d use a layered system rather than trying to read every EPA update. The key is to distinguish what EPA is proposing, what has actually become law, and how your state implements it.

The core resources

1. EPA Laws & Regulations hub — Your starting point. It organizes Clean Air Act, Clean Water Act, RCRA, CERCLA, TSCA, FIFRA, drinking water, PFAS, compliance, enforcement, and guidance.

2. EPA Regulations page — Particularly useful for following rulemakings, finding 40 CFR, and navigating to Regulations.gov and the Federal Register. EPA specifically recommends these as tools for tracking regulations and participating in rulemaking.

3. eCFR — Title 40 — Probably the most important day-to-day reference. Title 40 contains the federal environmental regulations, and the eCFR is updated daily. Remember that it's an unofficial editorial compilation, so use the Federal Register when you need to establish exactly what was legally published or amended.

4. Federal Register — The place to watch proposed rules, final rules, notices, effective dates, and comment deadlines. For an engineer, I'd pay particular attention to the Summary, Dates, Addresses, Supplementary Information, and regulatory text rather than reading every page.

5. Regulations.gov — Essential when you're actually working with a rulemaking. You can find the docket, technical supporting documents, comments, EPA responses, and submit comments. EPA identifies it as its official online comment system.

6. EPA's Regulatory Agenda / Unified Agenda — Excellent for seeing what's coming before it happens. EPA publishes its Semiannual Regulatory Agenda twice a year, while the Regulatory Plan highlights the agency's most important anticipated actions.

Don't overlook your state

For practical engineering work, federal regulations are only half the picture. Your state's environmental agency, delegated programs, permits, and state-specific standards can be more immediately important than an EPA rule.

Since you're in Arizona, I'd put the Arizona Department of Environmental Quality (ADEQ) near the top of your monitoring list, especially for air, water, waste, remediation, and permitting.

Professional/technical sources

For interpretation rather than primary legal authority, I'd also follow:

• Air & Waste Management Association (A&WMA) — particularly strong for air, emissions, waste, and regulatory developments.
• American Society of Civil Engineers (ASCE) — useful for water, infrastructure, and environmental engineering.
• American Water Works Association (AWWA) — excellent if you're involved in drinking water.
• Water Environment Federation (WEF) — wastewater/stormwater and Clean Water Act issues.
• Environmental Council of the States (ECOS) — particularly useful for understanding how state environmental agencies are approaching federal changes.

A practical monitoring routine

I'd set it up like this:

Daily/near-daily: Federal Register alerts for your specific subjects
→ Weekly: EPA news + Regulations.gov activity
→ Monthly: review important proposed/final rules and their dockets
→ Twice yearly: EPA Regulatory Agenda
→ Whenever you're applying a requirement: verify against eCFR + Federal Register + applicable state rules/permit

That last step matters especially right now. EPA's regulatory landscape is changing rapidly; for example, EPA has recently proposed significant changes involving NEPA implementation and minor-source New Source Review.

If I were building an environmental engineer's "regulatory dashboard," my top five would be: eCFR + Federal Register + Regulations.gov + EPA Regulatory Agenda + your state environmental agency. Everything else is primarily there to help you interpret those primary sources.