NC State Extension Publications


Improving drainage of poorly drained soils improves trafficability for timely field operations. In addition, drainage improves crop yield by eliminating long periods of excess water. An important advantage of subsurface drains is that drainage occurs without taking land out of production. In North Carolina, subsurface drains are generally installed with closer spacing than typical open ditches. Subsurface drains, along with good surface drainage, effectively protect crops from excessive soil water conditions.

Subsurface drainage cost in North Carolina can vary greatly depending on location and is highly dependant on soil properties. The most important soil property affecting the cost per acre for drainage installation is soil texture, which determines the ability of the soil to move water both vertically and laterally. Figure 1 and Table 1 show the estimated costs of material and installation for subsurface drainage pipes in North Carolina with varying drain spacing. These cost estimates are based on 50 cents per linear foot of 4-inch perforated drains with fabric filter and average installation cost of 60 cents per linear foot. Installation cost may vary depending on the number of acres drained, drain depth, connections, system design, and ease of installation. The material cost of 4-inch drains may also vary depending on the supplier and whether fabric filters are included. A fabric filter prevents fine sands from entering and clogging the drains. You should choose the drain spacing that provides adequate drainage while avoiding unnecessary installation costs.

Graph of cost per acre (y-axis) and drain spacing (x-axis)

Figure 1. Estimated per acre subsurface drainage cost (50 cents per linear foot for 4-inch drains with fabric; 60 cents per linear foot for installation).


Table 1. Estimated per acre subsurface drainage cost (50 cents per linear foot for 4-inch drains with fabric; 60 cents per linear foot for installation)

Spacing $/ac
30 $1,597
40 $1,198
50 $958
60 $799
70 $685
80 $599
90 $532
Spacing $/ac
100 $479
110 $436
120 $399
130 $369
140 $342
150 $319
160 $299
Spacing $/ac
170 $282
180 $266
190 $252
200 $240
210 $228
220 $218
230 $208
Spacing $/ac
240 $200
250 $192
260 $184
270 $177
280 $171
290 $165
300 $160


Assistant Professor and Extension Specialist
Biological & Agricultural Engineering
Biological & Agricultural Engineering
William Neal Reynolds and Distinguished University Professor Emeritus
Biological & Agricultural Engineering

Publication date: Jan. 10, 2020

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