Wastewater

Guidelines for Sizing

Features
These guidelines cover the steps which need
to be taken to accurately select the correct
sewage pump and applicable systems to use in
sewage ejectors.
Work through the five steps below to size
the system:
System capacity (gpm required)
Total head
Pump selection
Solids handling
Basin size
Simplex/Duplex system

Wastewater Water Systems HVAC Industrial Engineered Products

Guidelines for Sizing

Figure 2.

System Capacity
System Capacity refers to the rate of flow in gallons per
minute (gpm) necessary to efficiently maintain the system.
The Fixture Unit method is suggested for determining this
figure. This approach assigns a relative value to each fixture or
group of fixtures normally encountered. Determination of the
required System Capacity is as follows:
List all fixtures involved in the installation and using
Figure 1, assign a Fixture Unit value to each. Add to
obtain total.

200

100
90
80
70
60
50
40

Referring to Figure 2, locate the total Fixture Unit amount

along the horizontal axis of the graph and follow vertically
until intersecting the plotted line. Read the System
Capacity in gpm along the vertical axis.

30

20

Figure 1.
10

Fixture Description
Bathroom group, consisting of lavatory, bathtub
or shower and (direct flush) water closet

10

Bathroom group, consisting of lavatory, bathtub

or shower and (flush tank) water closet

Bathtub with 1-1/2" trap

Bathtub with 2" trap

Bidet with 1-1/2" trap

Dental unit or cuspidor

Drinking fountain

Dishwasher (domestic type)

Kitchen sink (domestic)

Kitchen sink (domestic with waste grinder)

Lavatory with 1-1/2" trap

Lavatory (barber or beauty shop)

Laundry tray (2-compartment)

Shower stall

Shower (group), per head

Sink (service type with floor drain)

Sink (scullery)

Sink (surgeons)

Urinal (with flush valve)

Urinal (with flush tank)

Water closet (flush valve)

Water closet (flush tank)

Swimming pools (per 1000 gal. capacity)

Unlisted fixture with 1-1/4" trap size

Unlisted fixture with 1-1/2" trap size

Unlisted fixture with 2" trap size

Unlisted fixture with 2-1/2" trap size

Unlisted fixture with 3" trap size

Unlisted fixture with 4" trap size

Water softener (domestic)

Washing machine

2
TOTAL

10

20

30

40

50 60 70 8090100

200 300

400

500 600

Unit Total
Value Used

Total Head
Total Head is a combination of two components Static Head
and Friction Head and is expressed in feet (refer to Typical
Installation illustration, Figure 3).
Static Head is the actual vertical distance measured from the
minimum water level in the Basin to the highest point in the
discharge piping.
Friction Head is the additional head created in the discharge
system due to resistance to flow within its components. All
straight pipe, fittings, valves, etc. have a friction factor which
must be considered. These friction factors are converted to,
and expressed as, equivalent feet of straight pipe, which can
then be totaled and translated to Friction Head depending on
the flow and pipe size. Basically, this is reduced to four steps.
1. It will be necessary to determine the discharge pipe size. In
order to ensure sufficient fluid velocity to carry solids, (generally
accepted to be 2' per second), flows should be at least:

9 gpm through 1-1/4" pipe

13 gpm through 1-1/2" pipe
21 gpm through 2" pipe
30 gpm through 2-1/2" pipe
46 gpm through 3" pipe

2. The length of the discharge piping is measured from the

discharge opening of the pump to the point of final discharge,
following all contours and bends.
3. To determine the equivalent length of discharge piping represented by the various fittings and valves, refer to Figure
5 and total all values. Add this to the measured length of
discharge pipe and divide by 100 to determine the number
of 100' increments.
4. Refer to Figure 4 and find the required Pump Capacity
(determined from Figure 2). Follow gallons per minute to
pipe size being used. Multiply this number by the number
of 100' increments.
Add the Static Head and Friction Head to determine Total Head.

Guidelines for Sizing

Figure 3.

Figure 4.

Plastic Pipe:Friction Loss (in feet of head) per 100 Ft

Req'd
Pump
Capacity
GPM
1
2
3
4
5
6
8
10
15
20
25
30
35
40
45
50
60
70
80
90
100
125
150
175
200
250
300
350

1-1/4"
ft
.10
.21
.35
.51
.71
1.19
1.78
3.75
6.39
9.71
13.62
18.17
23.55
29.44

1-1/2"
ft

.10
.16
.24
.33
.55
.83
1.74
2.94
4.44
6.26
837
10.70
13.46
16.45
23.48

2"
ft

.10
.17
.25
.52
.86
1.29
1.81
2.42
3.11
3.84
4.67
6.60
8.83
11.43
14.26

2-1/2"
ft

.11
.22
.36
.54
.75
1.00
1.28
1.54
1.93
2.71
3.66
4.67
5.82
7.11
10.83

3"
ft

.13
.19
.26
.35
.44
.55
.66
.93
1.24
1.58
1.98
2.42
3.80
5.15
6.90
8.90

4"
ft

.09
.12
.15
.17
.25
.33
.41
.52
.63
.95
1.33
1.78
2.27
3.36
4.85
6.53

Guidelines for Sizing

Figure 5.

Friction Factors for Pipe Fittings

In Terms of Equivalent Feet of Straight Pipe
TEE
TEE
SWING
NOMINAL
90
45
(THROUGH (BRANCH CHECK GATE
PIPE SIZE ELBOW ELBOW
FLOW)
FLOW)
VALVE VALVE
1-1/4

3.5

1.8

2.3

6.9

11.5

1-1/2

4.0

2.2

2.7

8.1

13.4

0.9
1.1

5.2

2.8

3.5

10.3

17.2

1.4

2-1/2

6.2

3.3

4.1

12.3

20.3

1.7

7.7

4.1

5.1

15.3

25.5

2.0

Total Head Required

(A) STATIC HEAD
(B) TOTAL LENGTH OF PIPING
(C) TOTAL FRICTION FACTORS OF FITTINGS
(D)

(E)

TOTAL (B+C)
DIVIDED (D) BY 100

(F) HEAD LOSS PER 100 FT. OF PIPE (from Figure 4)

(G)

FRICTION HEAD (ExF)

(H)

TOTAL HEAD (A+G)

Pump Selection
Every centrifugal pump has a unique performance curve. This
curve illustrates the relationship of flow (gpm) to pressure
(Total Head) at any point. The pump will operate at any point
along this performance curve.
Pump capacity is therefore the flow the pump will generate
at any specific pressure. The object is to select a pump whose
performance curve passes either through or close to the
design condition, preferably above. Refer to Figure 7.

Solids Handling
Solids Handling requirements may be determined by local
codes and/or by the type of application and types of solids
anticipated. Unless otherwise stated by codes, a sewage
pump should have the capability of handling spherical
solids of at least 2" in diameter in installations involving a
water closet.

Basin Size
Basin selection is best accomplished by relating to required
System Capacity as determined by the Fixture Unit method.
Figure 6 shows recommended basin diameters, assuming the
normal pump differential (distance in inches between turn-on
and turn-off), and running time ranges from 15 seconds
to 4 minutes. Basin depth, however, should be at least 24"
below basin inlet for most pumps and deeper where greater
pumping differentials are anticipated.
NOTE: Since basin size is directly related to frequency of
pump operation, it is important to select a basin of sufficient
size to ensure that the pump does not short cycle.

The question of whether to use a Simplex or Duplex system

depends on the type of installation and/or local codes. Generally,
a determination can be made using the following guidelines.
1. Domestic: Simplex System is usually adequate.
2. Commercial: Optional Depending on the type of business
and the need for uninterrupted sanitary drainage facilities.
3. Public or Industrial: Duplex System is essential.
While you are sizing the system and before you select the
pump, you will need to know and consider or make allowances
for the following:
Volts/Phase/Hertz What is available?
Will the pump share a circuit?
Does the home, business, etc. have circuit breakers or fuses?
What is the breaker or fuse Amp rating? Make sure it is enough.
Check local or state codes for:
Solid size requirements
Amp ratings/circuit cord size/ratings or type
Pipe material/size/depth to bury
Tank size/location
Are there plans for future expansion? As in, adding
upstairs bath, basement plumbing, washing machine, etc.

Guidelines for Sizing

BASIN SIZING

Figure 6.

BASIN DIAMETER (inches)

18"

24"

30"

36"

42"

48"

GALLONS/FOOT
OF BASIN DEPTH

13.2

23.9

36.7

52.9

72.0

94.0

GALLONS IN 2-1/2'
OF BASIN DEPTH

33.0

59.7

91.7

132.2

180.0

235.0

20
25
30
SYSTEM CAPACITY (GPM)

35
40
45
50
60
70
80
90
100
125
150
175
200
225

Select minimum basin depth so that 2-1/2' of basin depth in gallons = Pump capacity in gpm
= Acceptable basin size

Guidelines for Sizing

Example Sizing Problem
What Pump Capacity would be required to handle the drainage
from a 4 bathroom home, also including a dishwasher, a washer,
a laundry tray, a kitchen sink, water softener, basement shower,
a 13,000 gallon pool, and a bar sink (1-1/2" trap)?
1. From Figure 1:
Description

Fixture
Units

Four bathroom groups

24

Water softener

Dishwasher

Washing machine

Laundry tray

Kitchen sink with disposal

Basement shower

Swimming pool

13

Bar sink (unlisted 1-1/2")

FIXTURE UNITS TOTAL

55

2. Refer to Figure 2:
Find 55 Fixture Units on the horizontal axis. Follow vertically
until intersecting the line then horizontally to the left. The
Pump Capacity on the vertical axis is 30 gpm.

c. Refer to Figure 6 and note the friction factor in equivalent

feet for each fitting:

3 - 90 elbows, 2"

16 - equivalent feet

1 - gate valve, 2"

1 - equivalent foot

1 - swing check valve, 2" 17 - equivalent feet

Total:

34 - equivalent feet

Adding 34' to the measured pipe length, the total effective

pipe length becomes 234' or 2.34 100' increments.
d. Refer to Figure 4, find the 30 gpm required Pump Capacity
on the left scale and follow over to the 2" PVC pipe size
column. Friction Head is 1.8 x 2.34 = 4.2'.
3. Total Head Required:
Total Head = Static Head + Friction Head
Example:

Total Head = 7 + 4.2

Total Head = 11.2

Due to the existence of water closets in this installation, a

pump with 2" Solids Handling capacity should be used unless
otherwise specifically stated by applicable codes. Use Figure
7 to select pump.

Determine the Total Head of the installation illustrated in

Figure 3, the Typical Installation Illustration:

To determine the Basin size, find the Pump Capacity (30 gpm)
in the column on the left of Figure 6. Any Basin diameter of 18"
or greater is acceptable.

1. That Static Head in this instance is 7'.

Since this application is domestic, a Simplex System is sufficient.

2. Friction Head:
a. Since the required Pump Capacity in this illustration of
30 gpm is less than the 46 gpm necessary to carry solids
through 3" pipe, 2" or 2-1/2" pipe should be used. If 3"
pipe is preferred or required, a Pump Capacity of at least
46 gpm is required.
b. Measurement of the length of the discharge pipe
totals 200'.

Summary: Recommended selections for this installation would

be a Simplex System utilizing an 18" or greater diameter Basin
and a 2" Solids Handling pump capable of delivering at least
30 gpm at 11'.

Guidelines for Sizing

Summary Worksheet

Number of Fixture Units

______________________________________

Flow Rate - Gallons Per Minute

______________________________________

Total Head Required

______________________________________

Pump Selection

______________________________________

Typical Single Family Dwelling Sewage Pump Chart

Note: The data contained herein is for reference only. Proper sizing and selection of sewage pumps requires consideration of many factors. Always
consult applicable local codes before installing any equipment. This chart is based on a residential application with not more than 34 fixture units (values
assigned to each plumbing fixture). The TDH (Total Dynamic Head) of the system is calculated based on total vertical lift, horizontal length of discharge
piping, and the friction losses for 2 diameter plastic pipe (3 diameter plastic pipe where the 16S pump is shown).

Total Length of Discharge Pipe in Feet

100'

150'

200'

250'

300'

350'

400'

450'

500'

550'

600'

650'

700'

750'

800'

TDH
PUMP
GPM

TDH
PUMP
GPM

TDH
PUMP
GPM

TDH
PUMP
GPM

TDH
PUMP
GPM

TDH
PUMP
GPM

TDH
PUMP
GPM

TDH
PUMP
GPM

TDH
PUMP
GPM

TDH
PUMP
GPM

TDH
PUMP
GPM

TDH
PUMP
GPM

TDH
PUMP
GPM

TDH
PUMP
GPM

TDH
PUMP
GPM

5'

6.3'
9SN
97 gpm

7.0'
9SN
95 gpm

7.5'
9SN
92 gpm

8.3'
9SN
88 gpm

8.9'
9SN
82 gpm

9.6'
9SN
77 gpm

10.2'
9SN
72 gpm

10.9'
9SN
67 gpm

11.5'
9SN
61 gpm

12.2'
9SN
54 gpm

12.8'
9SN
48 gpm

13.5'
9SN
43 gpm

14.1'
9SN
38 gpm

14.8'
9SN
32 gpm

15.4'
9SN
27 gpm

6'

7.3'
9SN
93 gpm

8.0'
9SN
89 gpm

8.6'
9SN
83 gpm

9.3'
9SN
78 gpm

9.9'
9SN
75 gpm

10.6'
9SN
69 gpm

11.2'
9SN
63 gpm

11.9'
9SN
57 gpm

12.5'
9SN
52 gpm

13.5'
9SN
43 gpm

13.8'
9SN
40 gpm

14.5'
9SN
33 gpm

15.1'
9SN
29 gpm

15.8'
9SN
25 gpm

16.4'
10SN
57 gpm

7'

8.3'
9SN
88 gpm

9.0'
9SN
81 gpm

9.6'
9SN
77 gpm

10.3'
9SN
70 gpm

10.9'
9SN
67 gpm

11.6'
9SN
59 gpm

12.2'
9SN
54 gpm

12.9'
9SN
47 gpm

13.5'
9SN
43 gpm

14.2'
9SN
36 gpm

14.8'
9SN
32 gpm

15.5'
9SN
26 gpm

16.1'
10SN
62 gpm

16.8'
10SN
54 gpm

17.4'
10SN
48 gpm

8'

9.3'
9SN
78 gpm

10.0'
9SN
76 gpm

10.6'
9SN
69 gpm

11.3'
9SN
62 gpm

11.9'
9SN
57 gpm

12.6'
9SN
50 gpm

13.2'
9SN
45 gpm

13.9'
9SN
39 gpm

14.5'
9SN
33 gpm

15.2'
9SN
28 gpm

15.8'
9SN
25 gpm

16.5'
10SN
56 gpm

17.1'
10SN
52 gpm

17.8'
10SN
46 gpm

18.4'
10SN
41 gpm

9'

10.3'
9SN
70 gpm

11.0'
9SN
65 gpm

11.6'
9SN
59 gpm

12.3'
9SN
53 gpm

12.9'
9SN
47 gpm

13.4'
9SN
44 gpm

14.2'
9SN
36 gpm

14.9'
9SN
30 gpm

15.5'
9SN
26 gpm

16.2'
10SN
60 gpm

16.8'
10SN
54 gpm

17.5'
10SN
48 gpm

18.1'
10SN
42 gpm

18.8'
10SN
39 gpm

19.4'
10SN
33 gpm

10'

11.3'
9SN
62 gpm

12.0'
9SN
56 gpm

12.6'
9SN
50 gpm

13.3'
9SN
44 gpm

13.9'
9SN
39 gpm

14.6'
9SN
33 gpm

15.2'
9SN
28 gpm

15.9'
10SN
62 gpm

16.5'
10SN
56 gpm

17.2'
10SN
50 gpm

17.8'
10SN
46 gpm

18.5'
10SN
40 gpm

19.1'
10SN
35 gpm

19.8'
10SN
32 gpm

20.4'
10SN
27 gpm

11'

12.3'
9SN
53 gpm

13.0'
9SN
46 gpm

13.6'
9SN
42 gpm

14.3'
9SN
35 gpm

14.9'
9SN
30 gpm

15.6'
9SN
25 gpm

16.2'
10SN
60 gpm

16.9' 1
10SN
53 gpm

17.5'
10SN
48 gpm

18.2'
10SN
42 gpm

18.8'
10SN
39 gpm

19.5'
10SN
33 gpm

20.1'
10SN
29 gpm

20.8'
10SN
25 gpm

21.4'
14S
27 gpm

12'

13.3'
9SN
44 gpm

14.0'
9SN
40 gpm

14.6'
9SN
33 gpm

15.3'
9SN
27 gpm

15.9'
10SN
62 gpm

16.6'
10SN
55 gpm

17.2'
10SN
50 gpm

17.9'
10SN
45 gpm

18.5'
10SN
40 gpm

19.2'
10SN
34 gpm

19.8'
10SN
32 gpm

20.5'
10SN
26 gpm

21.1'
14S
30 gpm

21.8'
14S
26 gpm

16.4'
16S
120 gpm*

13'

14.3'
9SN
35 gpm

15.0'
9SN
29 gpm

15.6'
9SN
25 gpm

16.3'
10SN
58 gpm

16.9'
10SN
53 gpm

17.6'
10SN
47 gpm

18.2'
10SN
42 gpm

18.9'
10SN
37 gpm

19.5'
10SN
33 gpm

20.2'
10SN
28 gpm

20.8'
10SN
25 gpm

22.0'
14S
25 gpm

14'

15.3'
9SN
27 gpm

16.0'
10SN
61 gpm

16.6'
10SN
55 gpm

17.3'
10SN
49 gpm

17.9'
10SN
45 gpm

18.6'
14S
39 gpm

19.2'
10SN
34 gpm

19.9'
10SN
31 gpm

20.5'
10SN
26 gpm

21.2'
14S
29 gpm

21.8'
14S
26 gpm

15'

16.3'
10SN
58 gpm

17.0'
10SN
52 gpm

17.6'
10SN
47 gpm

18.3'
10SN
41 gpm

18.9'
10SN
37 gpm

19.6'
10SN
33 gpm

20.2'
10SN
28 gpm

20.9'
10SN
25 gpm

21.5'
14S
27 gpm

22.2'
14S
25 gpm

16'

17.3'
10SN
49 gpm

18.0'
10SN
44 gpm

18.6'
10SN
39 gpm

19.3'
10SN
33 gpm

19.9'
10SN
31 gpm

20.6'
10SN
25 gpm

21.2'
14S
29 gpm

21.9'
14S
26 gpm

17'

18.3'
10SN
41 gpm

19.0'
10SN
36 gpm

19.6'
10SN
33 gpm

20.3'
10SN
27 gpm

20.9'
10SN
25 gpm

21.6'
14S
26 gpm

22.2'
14S
25 gpm

18'

19.3'
10SN
33 gpm

20.0'
10SN
30 gpm

20.6'
10SN
25 gpm

21.3'
14S
28 gpm

21.9'
14S
26 gpm

19'

20.3'
10SN
27 gpm

21.0'
14S
30 gpm

21.6'
14S
26 gpm

22.3'
14S
25 gpm

20'

21.3'
14S
28 gpm

22.0'
14S
25 gpm

21.6'
16S
95 gpm*

21.9'
16S
95 gpm*

TOTAL
VERT.
LIFT

17.6'
17.9'
18.2'
16S
16S
16S
113 gpm* 112 gpm* 111 gpm*

17.6'
17.9'
18.2'
18.4'
16S
16S
16S
16S
113 gpm* 112 gpm* 111 gpm* 110 gpm*

18.3'
18.6'
18.9'
19.2'
19.4'
16S
16S
16S
16S
16S
110 gpm* 109 gpm* 107 gpm* 105 gpm* 104 gpm*

18.8'
19.1'
19.3'
19.6'
19.9'
20.2'
16S
16S
16S
16S
16S
16S
107 gpm* 105 gpm* 104 gpm* 103 gpm* 101 gpm* 98 gpm*

21.2'
16S
95 gpm*

19.5'
19.8'
20.0'
20.3'
16S
16S
16S
16S
103 gpm* 102 gpm* 100 gpm* 99 gpm*

20.6'
16S
98 gpm*

20.9'
16S
97 gpm*

21.2'
16S
95 gpm*

22.4'
16S
95 gpm*

19.9'
20.2'
16S
16S
101 gpm* 98 gpm*

20.5'
16S
98 gpm*

20.8'
16S
97 gpm*

21.1'
16S
96 gpm*

21.3'
16S
95 gpm*

22.6'
16S
93 gpm*

21.9'
16S
91 gpm*

22.2'
16S
90 gpm*

22.4'
16S
89 gpm*

20.7'
16S
98 gpm*

21.0'
16S
96 gpm*

21.2'
16S
95 gpm*

22.5'
16S
94 gpm*

21.8'
16S
92 gpm*

22.1'
16S
91 gpm*

22.3'
16S
90 gpm

22.6'
16S
86 gpm*

22.9'
16S
84 gpm*

23.2'
16S
82 gpm*

23.4'
16S
81 gpm*

22.2'
16S
95 gpm*

22.5'
16S
88 gpm*

22.8'
16S
85 gpm*

23.1'
16S
83 gpm*

23.4'
16S
81 gpm*

23.7'
16S
80 gpm*

24.0'
16S
79 gpm*

24.3'
16S
78 gpm*

24.6'
16S
77 gpm*

24.9'
16S
76 gpm*

25.2'
16S
75 gpm*

Guidelines for Sizing

Figure 7.

Flow - Liters/Minute
0

118

236

354

472

590

80

708

826
24

70
18
20S

50
40

18S

30

ES60

12

16S

Head - Meters

Head - Feet

60

14S

20

ES50

10

ES40

10SN
9SN

0
0

20

40

60

0
80 100 120 140 160 180 200 220
Flow - Gallons/Minute

P.O. Box 12010

Oklahoma City, OK 73157-2010
Phone: 1.800.701.7894
Fax: 1.800.678.7867
www.LittleGiantPump.com

Form 993391 01/13