Md. Code Regs. 26.04.04.17

Current through Register Vol. 51, No. 12, June 14, 2024

Section 26.04.04.17 - Construction Standards-Casing

A. Well Casing.

(1) Markings.

(a) Except as provided in §A(1)(b) of this regulation, all casing shall be marked by the manufacturer sufficiently to allow identification of the casing.

(b) Well casing for monitoring wells is exempt from displaying markings.

(c) The well driller shall provide, upon request, sufficient information to allow identification of casing used for monitoring wells.

(2) Plastic Well Casing.

(a) Plastic well casing shall be polyvinyl chloride, PVC, manufactured to meet the standards of the American Society of Testing and Materials (ASTM) Standard F-480.

(b) Plastic well casing shall be installed in accordance with the maximum depth limits specified:

Table 1

Depth Limit, In Feet, for Plastic Water Well Casing

PVC Cell Class 12454, PVC 1120, Type I

Diameter (inches)	SDR	SDR	SDR	SDR	SCH	SCH
26	21	17	13.5	40	80
2	136	265	517	1085	708	2185
3	"	"	"	"	604	1730
4	"	"	"	"	400	1139
4.5	"	"	"	"	310	M
5	"	"	"	"	242	807
6	"	"	"	"	180	724
8	"	"	"	"	125	498
10	"	"	"	"	92	424
12	"	"	"	"	76	387
16	"	"	"	"	72	-

(c) In Hydrogeologic Areas 3, 4 ,and 5, plastic well casing may not be used for the main casing where caving conditions occur before casing placement.

(d) Plastic well casing 4 inches or less in diameter shall be a minimum of schedule 40.

(e) All plastic well casing greater than 4 inches in diameter shall be a minimum of SDR 26.

(3) Metal Well Casing.

(a) Metal well casing shall meet one of the following standards:

(i) ASTM standard A-53 or A-589;

(ii) American Petroleum Institute standard 5A or 5L; or

(iii) ASTM standard A312, type 304 minimum, for stainless steel.

(b) Metal well casing of 4 inches or less, nominal size, shall be schedule 40 or better.

(c) Metal well casing greater than 4 inches, nominal size, shall have a minimum nominal wall thickness of 0.188 inches.

(d) The Approving Authority may require that Schedule 40 or Standard Schedule metal well casing be used where there is corrosive water, soil, or geology.

(e) Metal casing shall be new, prime pipe, being free of pits or breaks.

(4) Casing material is not permitted which will cause the delivered water to be toxic or violate State or federal primary drinking water standards in effect at the time the well is constructed.

(5) Other types and sizes of well casing may be approved by the Approving Authority for special applications, upon written request by the well driller.

B. Minimum Casing Length.

(1) In Hydrogeologic Areas 1 and 2, the casing shall extend to the top of or into the aquifer used.

(2) In Hydrogeologic Areas 3, 4, and 5, the casing shall extend through the weathered zone and be seated a minimum of 2 feet into bedrock.

(3) Less than 20 feet of casing may not be used in any area except as provided in Regulation .23 of this chapter.

(4) In Hydrogeologic Area 4, the minimum casing length is 40 feet.

C. Minimum Casing Diameter.

(1) Potable water supply wells shall have a minimum main casing diameter of 4 inches in all hydrogeologic areas of the State.

(2) In Hydrogeologic Areas 1 and 2, for potable water supply wells, the 4-inch minimum main casing diameter shall extend to, whichever comes first:

(a) A minimum of 250 feet; or

(b) The top of the aquifer used.

(3) Criteria for Variance for Telescoping Casing.

(a) The Approving Authority shall submit a report to the Department for approval prior to granting variances to §C(2) of this regulation for increasing or decreasing the minimum depth of the 4-inch minimum main casing diameter.

(b) The report shall contain at a minimum the following information:

(i) Area of county where variance is being considered;

(ii) Aquifer for which variance is being considered;

(iii) Discussion of current aquifer usage and predicted aquifer usage; and

(iv) Proposed variance wording.

(c) The report shall be incorporated in the county Master Water and Sewer Plan prior to implementation.

D. Well Casing Joints.

(1) Joints shall be watertight.

(2) Joints for metal casing may be either electrically welded or threaded.

(3) Joints for plastic well casing may be either threaded, solvent welded, or o-ring.

(4) Screws or other mechanical devices may only be used to join PVC well liner:

(i) For solvent welded joints used in liners,

(ii) With nonpenetrating stainless steel screws,

(iii) And per the recommendations of the pipe manufacturer to maintain their warranty.

E. Other Installation Requirements.

(1) Liners shall meet the standards for well casing under §§A and D of this regulation.

(2) Well casing may not be cut off or cut into below ground except to install a pitless unit.

(3) Well casing shall extend at least 8 inches above the finished grade.

Md. Code Regs. 26.04.04.17

Regulations .17 adopted effective 42:1 Md. R. 19, eff.1/15/2015