Petroleum Product Storage: Assessing Drinking Water Contamination Risk

For each category listed on the left that is appropriate to your situation, click the box under rank 1-4 that best applies. Your "rank number" will then be genrated on the right.

Glossary for this Fact Worksheet

Information for this Fact Worksheet (PDF)

 

Please Select Your County:

Location (Addressed in Section 1)

 
Low Risk
(rank 4)
Low-Mod Risk
(rank 3)
Mod-High Risk
(rank 2)
High Risk
(rank 1)
Your Rank

1. Position of tank in relation to drinking water well

 Tank more than 400 feet downslope from well. Tank less than 400 feet, but more than 150 feet downslope from well. Tank less than 150 feet, but more than 50 feet downslope from well. Tank less than 50* feet or upslope from well.

 

 

2. Site characteristics of tank location

Soil Type:

 Medium- or fine-textured soils (silt loam, loam, clay loams, silty clay) with low permeability.** Medium- or fine-textured soils with moderate permeability.** Coarse-textured soils (sand, sandy loam) with moderate-permeability.** Coarse-textured soils with high permeability.**

 

 
Water table depth: Greater than 99 feet 50-99 feet 20-49 feet Less than 20 feet

 

 

Design And Installation (Addressed in Section 2)

3. Type and age of tank/corrosion protection

(Underground tanks)

 Double-walled tank. Single walled steel tank
with cathodic protection or fiberglass tank.		 Unprotected single walled steel tank equal to or less than 10 years of age. Unprotected single walled steel tank greater than 10 years of age.

 

 
4. Above-ground tanks Doubled-walled tank placed within concrete or synthetic dike with pad able to hold 110 percent of tank capacity. UL 142 labeled. Tank placed within dike and pad lined with low permeability soils,** able to hold 110 percent of tank capacity. UL 142 labeled. Tank placed on pad with no dike. UL 142 labeled. No secondary containment. Not UL 142 labeled.

 

 
*Illegal for new public water supply well installation. Existing wells must meet separation requirements in effect at time of construction.
**Low permeability soils like clay allow water to flow through slowly. High permeability soils like sand and gravel allow much faster water movement.

Design And Installation (continued )
5. Underground
piping		 FRP* or steel piping with cathodic corrosion protection. Isolated from tank, sloped back to tank and suction system with check valve at pump. Double-walled pipe. Metal pipe with suction system. Pipe drains back to tank. Check valve at pump. Metal pipe with suction system. Pipe drains back to tank. Check valve at tank. Piping and tank of dissimilar materials. Pipe cannot drain freely to the tank. Single-walled, pressurized pipe system.

 

 
6. Above-ground
piping		 Steel pipe with anti-siphon protection and bumper guards. Steel pipe with anti-siphon protection. Metal pipe and hose. Nonmetal pipe.

 

 
7. Tank installation Underground tank-
installed by state-certified installer.

Above-ground tank-
inspected by appropriate authority.

 Installed according to recommendations supplied with new tank by seller. Installed without consulting guidelines for given application. Installed without backfill, setback, secondary containment, anchors, and other protections, or by untrained individual. No information on installation.

 

 

Mixing And Loading Practices (Addressed in Sections 2 and 3)
8. Spill and tank overfill protection Designed spill
containment. Overfill alarm with automatic shutoff.		 Designed spill containment. Overfill alarm or automatic shutoff. Either designed spill containment or overfill protection. No protection.

 

 
9. Above-ground tank security enclosure Tank surrounded by enclosure as required by Uniform Fire Code. Tank surrounded by fence with lock. Tank surrounded by fence. No lock. No enclosure.

 

 
* Fiberglass reinforced plastic.

Monitoring (Addressed in Section 3)

10. Tank integrity testing and leak detection monitoring Active leak detection system in place. Regular inventory control and annual tank tightness testing. Occasional inventory control and annual tank tightness testing. No inventory control, testing, or monitoring.

 

 

Underground Tank Removal And Closure (Addressed in Section 5)
11. Unused
underground tank		 Tank taken from ground according to regulations and by a state certified remover. Excavation checked for evidence of contamination and any contamination reported to the state.* Tank contents emptied and tank filled with inert material. Any
contaminated material around site removed.*		 Tank removed or filled with inert material. Excavation and site not checked for contamination. Tank not properly
removed, or improperly abandoned in-place.

 

 
* Petroleum releases are to be reported to the Division of Environmental Quality within 24 hours. Cleanup action may or may not be required depending on the type and extent of the release.