How to Draw an SPCC Facility Diagram for a Pennsylvania Site

What a Pennsylvania SPCC Site Diagram Needs to Show, and How to Build One From Aerial Imagery and Site Plans

A facility diagram is the page an EPA inspector uses as a guide for where to walk and what to look at, and in the SPCC Plans we review it's one of the pieces we most often find out of date or incomplete. It's usually an old site plan with a few tanks penciled in, a newer generator tank missing, no sign of where the drums and totes are kept, and nothing to show where spilled oil would end up. If your Pennsylvania facility stores oil, the drawing in your plan should match what's in your yard today, because EPA Region 3 inspectors hold the two up against each other.

This article covers what the federal rule requires a diagram to show, how to build one from aerial imagery and site plans, how to show drainage and nearby waters, and what a finished example looks like. If you'd rather have someone walk your site and draw it with you, you can reach out to RMA anytime. If you'd rather do it yourself, everything below should get you most of the way there.

Table of Contents

• What Does an SPCC Facility Diagram Have to Show?
• What Belongs on an SPCC Facility Diagram? A Checklist
• Why Do SPCC Facility Diagrams Come Up Deficient?
• How Do You Build an SPCC Facility Diagram From Aerial Imagery and Site Plans?
• What Does an Example SPCC Facility Diagram Look Like?
• How Do You Show Drainage, Storm Drains, and Nearby Waters on an SPCC Diagram?
• How Do You Keep an SPCC Facility Diagram Current at a Pennsylvania Facility?
• How Can RMA Help With Your SPCC Facility Diagram?
• Additional Information About SPCC Facility Diagrams

What Does an SPCC Facility Diagram Have to Show?

The federal oil spill rule, 40 CFR 112.7(a)(3), says an SPCC Plan has to describe the physical layout of the facility and include a facility diagram. The diagram has to mark the location and contents of each fixed oil storage container and the storage area where mobile or portable containers are kept. It also has to show any completely buried tanks that are otherwise exempt from SPCC, marked as exempt, and every transfer station and connecting pipe. That's the legal minimum, and the rest of this article is about meeting it well.

EPA's SPCC Guidance for Regional Inspectors, the document its inspectors work from, adds detail on how they read that language. Containers of 55 gallons or more belong on the diagram, and that includes oil-filled equipment like hydraulic systems and electrical transformers, not only tanks. Containers under 55 gallons and permanently closed containers don't have to appear. In Pennsylvania the enforcing agency is EPA Region 3, based in Philadelphia, and our overview of who enforces SPCC Plans explains how that works alongside the state's tank program. If you want the basics of when a plan is needed at all, start with our guide to what an SPCC Plan is.

PENNSYLVANIA SPCC PLANS & COMPLIANCE

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What Belongs on an SPCC Facility Diagram? A Checklist

Think of the diagram in two layers. The first is what the rule and EPA's inspector guidance treat as required. The second is what EPA recommends but doesn't require, and we draw it every time, because it supports the containment and drainage sections of the plan and it's what a fire crew or inspector looks for once they know where the oil is.

When a diagram gets crowded, EPA allows the capacities and contents to live in a companion table, as long as the diagram and the table use matching IDs. Drums and totes work the same way: the diagram shows the storage area, the plan estimates how many containers are normally there, and a log tracks the changes. Our article on whether 55-gallon drums count toward SPCC explains how drums are counted.

Why Do SPCC Facility Diagrams Come Up Deficient?

In a national review of SPCC Plans, EPA staff found an average of four plan deficiencies at each facility they reviewed, and the most common categories were plan content, general secondary containment, integrity testing, sized secondary containment, and drainage. The diagram touches several of those, because it's where a reviewer first sees whether your containment and drainage match the written plan. EPA enforcement filings have also alleged diagrams that left out regulated containers, storage areas, and connecting pipes. Our breakdown of the top SPCC Plan violations and fines shows where those findings usually land.

The patterns we see are consistent. The drawing is an old site plan with tanks penciled in, and the yard has changed since. Generator tanks, hydraulic reservoirs, transformers, and totes parked outside never made it onto the page. An exempt buried tank isn't shown, even though the rule says to show it. Piping is skipped, drainage isn't drawn at all, and the version in the binder is years older than the one people use. None of it takes a design degree to fix, only a site walk and someone willing to look in the corners. If you've already received an inspection report or an information request from EPA or DEP, an environmental attorney can help you decide how to respond. Our look at the most overlooked SPCC requirements covers other places plans tend to fall short.

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SPCC requirements, Tier I and Tier II plans, PE certification, costs, five-year reviews, and how RMA helps you develop your plan and stay compliant, all in one place.

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How Do You Build an SPCC Facility Diagram From Aerial Imagery and Site Plans?

You rarely need to start from a blank page. Most facilities already have a recent aerial image, an engineer's site plan or survey, or as-built drawings. An aerial image shows buildings, pavement, and surroundings, but it's often a year or more old, it can't see inside buildings, and tanks under canopies disappear. A site plan has accurate scale and often the storm sewer layout, but it was drawn before your current equipment arrived. We usually combine them, using the site plan for scale and drainage and the aerial image for context, and then correct both in the field.

What Are the Steps to Draw an SPCC Facility Diagram?

1. Pick a base and crop it. Frame the oil areas plus enough surrounding ground to show where water would go, and note the date of the imagery.
2. Add a north arrow and a real scale. Measure a known distance, such as a building wall, against the image's scale bar.
3. Walk the whole site with a printout. Go inside and behind buildings. Mark every container of 55 gallons or more, every piece of oil-filled equipment, every fill port, dispenser, and pipe run, and every spot where drums and totes are kept.
4. Read the labels. Check nameplates for capacity, and ask the people who use each container what's in it now.
5. Trace the water. Mark storm drain inlets, trench drains, ditches, culverts, and the nearest creek or pond, then draw the direction water would move.
6. Redraw it cleanly. Any tool works, from drawing software to a neat hand sketch. Give each item an ID that matches the container table in your plan.
7. Test it on a stranger. Someone who has never seen the site should be able to find every container from the diagram.

Keep one set of IDs across the diagram, the container table, and your monthly inspection checklist, and file a photo of each container with its ID visible. If your plan is PE-certified, the engineer reviews the diagram as part of certification, and EPA's guidance leaves the level of detail largely to that engineer's judgment. Our article on professional engineers and SPCC Plans explains when a PE is required.

How Do You Show Piping, Fill Ports, and Transfer Areas?

A transfer station is any place oil moves from one container to another: where a delivery truck connects, where a dispenser sits, where a generator gets filled. Mark each one and draw the connecting pipe. Where piping gets dense, EPA allows a single line labeled with its service, such as supply or return, or a box labeled piping, as long as more detailed drawings like blueprints are kept at the facility and referenced on the diagram.

What Does an Example SPCC Facility Diagram Look Like?

Here's a diagram for a made-up truck yard and equipment shop. It's schematic, and the capacities and distances are invented, so don't copy it for a real site. A real diagram should carry a true scale bar and be drawn from your own site. EPA publishes its own sample diagrams in Chapter 6 of the inspector guidance, plus example Tier I plans for a garage and a farm.

A companion container table carries the capacities and contents so the drawing stays readable.

Every container of 55 gallons or more has an ID, contents, and capacity. The drum area is drawn as an area, with a log kept separately. The buried gasoline tank is shown and marked exempt. The unloading pad, fill pipe, dispenser, and supply piping are all drawn, along with the dike, drain valve, two storm drain inlets, flow arrows, the creek, spill kits, a north arrow, and a legend.

The table also shows which kind of plan a site like this would use. The aboveground containers add up to 7,675 gallons, well over the 1,320 gallon threshold, and the exempt buried tank doesn't count toward that total. Because T-1 is over 5,000 gallons, EPA's Tier I template is off the table, since Tier I facilities have no single container over 5,000 gallons and no more than 10,000 gallons total aboveground. Our articles on the different types of SPCC Plans and Tier I self-certified plans explain how those categories work.

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SPCC requirements, Tier I and Tier II plans, PE certification, costs, five-year reviews, and how RMA helps you develop your plan and stay compliant, all in one place.

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How Do You Show Drainage, Storm Drains, and Nearby Waters on an SPCC Diagram?

SPCC exists to keep oil out of navigable waters and adjoining shorelines, so a diagram that shows containers but not the ground around them leaves out half the story. EPA's inspector guidance recommends marking storm drain inlets, surface waters a discharge could reach, and the direction oil would flow, and it notes that a diagram can answer the plan's drainage control and flow path requirements in picture form. The flow path ties to 112.7(b), which asks the plan to predict the direction, rate of flow, and total quantity of oil that could be discharged where experience shows a reasonable potential for equipment failure, such as a tank overflow or a hose failure at a loading area.

Don't guess where water goes. Start with the grading or drainage plan if you have one, then walk the site during or just after a rain, because flowing water and staining show you what a plan view can't. Ask your maintenance staff and your municipality where each inlet ends up. A parking lot inlet often connects to a municipal storm sewer that discharges to a local stream, but some inlets drain to on-site basins, some to sanitary sewers, and some to places nobody expected, so confirm each one. Mark the drain valves on dikes and their normal position, since a dike drain left open defeats the dike.

Show every ditch, swale, stream, pond, and wetland near the oil areas. Whether a given ditch counts as navigable waters under the Clean Water Act is a legal question that has shifted over the years, so we draw everything we can see and let the plan text address how each one is treated. If your site has stormwater permit coverage, its site map covers similar ground, and our comparison of SPCC Plans and SWPPPs explains where the two overlap. For how much containment each container needs, see our containment sizing article, and if oil does reach water, the reporting rules turn on a sheen, which we cover in our sheen rule guide.

How Do You Keep an SPCC Facility Diagram Current at a Pennsylvania Facility?

A diagram is accurate the day it's drawn and starts drifting the following week. The rule requires you to amend the plan when a change in the facility's design, construction, operation, or maintenance affects its potential for a discharge, and the plan needs a full review at least every five years. Our guide to five-year SPCC reviews walks through what that looks like. A new or removed tank, an added generator, a drum area that moved, new piping or containment, or a regrade that changes where water goes should each send someone back to the drawing. If you're adding a tank, the installation is work for your contractor, and for regulated tanks in Pennsylvania it may require DEP-certified installers. RMA doesn't handle installation or construction permits, but once the tank is in, updating the plan and the diagram to match is the part we help with.

Put the diagram in people's hands. EPA notes it can be attached to an inspection checklist, so carry it on your monthly walk and mark anything that doesn't match. Our list of what to check on monthly SPCC inspections has more, and our online training library is one way to make sure oil-handling staff can point to each container and drain.

Pennsylvania adds its own layer. DEP's storage tank program registers regulated tanks, owners of large aboveground storage tank facilities file a Spill Prevention Response Plan (SPRP), and other DEP programs may call for a Preparedness, Prevention and Contingency (PPC) Plan. EPA's guidance says a diagram prepared for another state or federal plan can be used in an SPCC Plan if it meets the SPCC rule, so one well-built drawing can often serve more than one plan, but check each plan's requirements before you assume it does.

PENNSYLVANIA SPCC PLANS & COMPLIANCE

Visit the Pennsylvania SPCC Plan Help Center

SPCC requirements, Tier I and Tier II plans, PE certification, costs, five-year reviews, and how RMA helps you develop your plan and stay compliant, all in one place.

Go to the Help Center

How Can RMA Help With Your SPCC Facility Diagram?

Plenty of facilities can draw their own diagram. If you have a handful of containers, simple piping, and a clear idea of where your drains go, the guidance above is enough, and you don't need a consultant. We help most on harder sites: a plan from another firm that doesn't match the yard, dense piping or a lot of oil-filled equipment, or a manager who wants someone to settle what counts. If your current plan came from another firm and the diagram is the weak spot, we usually rebuild the plan from scratch instead of patching someone else's work, and we'll tell you that up front.

Our staff walk the site and build the diagram and the plan together, and where a plan needs PE certification we work with an outside professional engineer. Some facilities are a good fit for remote development, and our article on whether remote SPCC development fits your facility can help you decide. SPCC Plans from RMA run about $1,500 to $15,000 depending on the size and complexity of the site, and we break the cost down in our SPCC cost guide.

There's no obligation in asking. You can call us at 888-RMA-0230, send an email, or fill out the form on our website, and we'll tell you whether you need us. To start that conversation, contact RMA whenever it suits you.