Analyzing 8,471,0258.5M ReviewsFor 24,07024.1K Experts
We graded 7 companies on seven things customers actually report: satisfaction, reliability, workmanship, value, momentum, track record and how owners handle complaints.
From 36,705 Google reviews of 82 top-rated septic tank services nationwide; 7 of them in Rockville, MD. Updated November 5, 2026.
Pick the job — we re-rank companies by how customers rated that exact job.
Experts Score 0–100Experts Score (0–100)Absolute quality first: recency-weighted star average (≈54%), share of 1–2★ reviews (≈24%), customers’ price verdicts (≈14%), owner replies to critical reviews (≈7%); minus up to 10 points each for complaints flagged in Google review highlights and for a real slide in recent ratings. Hover a company’s score on its page for the full breakdown. and a letter grade per factor (A = top 20% of septic tank services).
| # | Company | ScoreExperts Score (0–100)Absolute quality first: recency-weighted star average (≈54%), share of 1–2★ reviews (≈24%), customers’ price verdicts (≈14%), owner replies to critical reviews (≈7%); minus up to 10 points each for complaints flagged in Google review highlights and for a real slide in recent ratings. Hover a company’s score on its page for the full breakdown. | FactorsFactor grades, in orderSatisfaction (54%): Recency-weighted star average (2-year half-life), shrunk toward the category mean by review volume; the company’s own lifetime average as the prior; absolute: 4.0★ = 0, 5★ = 100.Reliability (24%): How rarely jobs go badly: share of 1–2★ reviews — 60% the last 24 months (or the 20 newest if fewer), 40% all-time; 0% = 100, 15%+ = 0; the category percentile can only raise it.Craft & service (0%): Google review highlights: Quality, Professionalism, Responsiveness, Punctuality — how rarely reviewers flag them as a negative, per review since highlights began; 0% = 100, 5%+ = 0. Subtracted from the score (up to −10), never averaged in — clean highlights are the norm, not a bonus.Value (14%): Customers’ own price verdicts (Great / Reasonable vs Overpriced) and Value highlights; 65% absolute (all “reasonable” ≈ 80, “great” = 100), the category percentile can only raise it.Momentum (0%): Penalises only a real slide: last-12-month average below lifetime (−0.5★ = 0). Still 4.8★+ over the last year, or steady/improving = 100. Subtracted from the score (up to −10), never averaged in.Replies to reviews (7%): How often the owner publicly replies to reviews under 5★ (1–4★). Needs 3+ such reviews, otherwise not counted; 65% absolute (80%+ replied = 100), the category percentile can only raise it.One letter per factor score: A = 80+, B = 60–79, C = 40–59, D = 20–39, F = below 20. | ★Google star rating as shown on Google Maps. | Typical billMedian bill customers of this company reported in their reviews (needs 3+ priced reviews). |
|---|---|---|---|---|---|
| 1 |  King & Sons Septic Service, LLCRockville, MD | A 98How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%99+54Reliability 24%99+24Value 14%100+14.1Replies to reviews 7%77+5.4Experts Score= 98Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAAB | 4.99 | $292 |
| 2 |  Environmental SepticRockville, MD | A 96How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 59%96+56.3Reliability 26%94+24.5Value 15%99+15.1Craft & service penalty99−0.1Experts Score= 96Not enough data for replies to reviews; its weight is shared by the others.Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAA– | 4.93 | $295 |
| 3 |  Heil Plumbing & HVACRockville, MD | A 95How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%96+52.4Reliability 24%96+23.3Value 14%98+13.9Replies to reviews 7%78+5.5Craft & service penalty96−0.4Experts Score= 95Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAAB | 4.96 | $608 |
| 4 |  Service Force PlumbingRockville, MD | A 94How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%93+50.7Reliability 24%93+22.5Value 14%98+13.9Replies to reviews 7%100+7.1Experts Score= 94Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAAA | 4.94 | $642 |
| 5 |  Service Force PlumbingRockville, MD | A 90How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%90+49.1Reliability 24%81+19.6Value 14%100+14.1Replies to reviews 7%100+7.1Experts Score= 90Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAAA | 4.93 | $447 |
| 6 |  Sky PlumbingRockville, MD | A 81How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%85+46.4Reliability 24%77+18.7Value 14%100+14.1Replies to reviews 7%65+4.6Craft & service penalty88−1.2Momentum penalty88−1.2Experts Score= 81Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | ABAAAB | 4.86 | — |
| 7 |  Roto-Rooter Plumbing & Water CleanupRockville, MD | B 73How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%80+43.6Reliability 24%74+17.9Value 14%50+7.1Replies to reviews 7%100+7.1Craft & service penalty87−1.3Momentum penalty82−1.8Experts Score= 73Grade B: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | ABACAA | 4.80 | $786 |
What customers paid, from the price Google asks reviewers to report.
| Job | Low25th percentile: 1 in 4 customers paid less than this. | TypicalMedian of the bill customers reported in their Google review (Google asks reviewers for a price range; we use the middle of each range). | High75th percentile: 1 in 4 customers paid more than this. | FairOf customers who rated the price, the share who chose “Great price” or “Reasonable” rather than “Overpriced”. |
|---|---|---|---|---|
| Drain cleaning | $228 | $328 | $493 | 97% |
| Plumbing pipe repair | $322 | $493 | $1.1k | 97% |
| Toilet repair | $216 | $351 | $593 | 95% |
| Plumbing leak detection | $104 | $264 | $618 | 96% |
| Sewer cleaning | $271 | $379 | $556 | 98% |
| Water heater installation | $1.2k | $1.9k | $2.4k | 97% |
| Plumbing leak repair | $271 | $454 | $1.1k | 95% |
| Faucet repair | $295 | $429 | $680 | 97% |
| Sewer repair | $393 | $1.2k | $2.1k | 98% |
| Faucet installation | $314 | $529 | $845 | 93% |
| Outdoor plumbing system repair | $328 | $529 | $1.2k | 98% |
| Shower repair | $161 | $317 | $466 | 97% |
How the 7 septic tank services we rated in Rockville, MD compare, and what customers praise most.
A = score 80+, F = below 20.
Average stars per company.
Share of Google review highlights.
All price verdicts left with reviews.
Share calling it great / reasonable / overpriced.
Satisfaction (54%) — Recency-weighted star average (2-year half-life), shrunk toward the category mean by review volume; the company’s own lifetime average as the prior; absolute: 4.0★ = 0, 5★ = 100.
Reliability (24%) — How rarely jobs go badly: share of 1–2★ reviews — 60% the last 24 months (or the 20 newest if fewer), 40% all-time; 0% = 100, 15%+ = 0; the category percentile can only raise it.
Craft & service (penalty, up to −10) — Google review highlights: Quality, Professionalism, Responsiveness, Punctuality — how rarely reviewers flag them as a negative, per review since highlights began; 0% = 100, 5%+ = 0. Subtracted from the score (up to −10), never averaged in — clean highlights are the norm, not a bonus.
Value (14%) — Customers’ own price verdicts (Great / Reasonable vs Overpriced) and Value highlights; 65% absolute (all “reasonable” ≈ 80, “great” = 100), the category percentile can only raise it.
Momentum (penalty, up to −10) — Penalises only a real slide: last-12-month average below lifetime (−0.5★ = 0). Still 4.8★+ over the last year, or steady/improving = 100. Subtracted from the score (up to −10), never averaged in.
Replies to reviews (7%) — How often the owner publicly replies to reviews under 5★ (1–4★). Needs 3+ such reviews, otherwise not counted; 65% absolute (80%+ replied = 100), the category percentile can only raise it.
The 7 best-rated septic tank services in Rockville, MD average 4.9★ on Google across 4,716 reviews. Heil Plumbing & HVAC has the top rating (5.0★), and Roto-Rooter Plumbing & Water Cleanup has the most reviews (1,238). Updated November 3, 2026.
7 companies that meet our bar: rated 4.5★ or higher on Google, with a meaningful review history (4,716 reviews combined) and currently operating. Request a call back and the company will phone you directly.
“Nothing but great things to say about our experience with this Heil Plumbing. Erik Young was our technician and he was very professional, thorough, and took care of everything we needed to get done quickly. He also…” — Google review
“Second time using this company, and we will continue to use them. On time, quick and courteous service. Very nice people.” — Google review
“Tyler was amazing! Strong communication, humorous, prompt, and amazing. Would work with again if any plumbing needs arise. Thank you Tyler!” — Google review
“We are just at getting the estimates stage of potentially replacing a main sewer pipe. Tyler from Service Force Plumbing was excellent. He patiently explained the video images as he was assessing the condition of our…” — Google review
“Mark was great. He arrived promptly within the scheduled window. It took him a while to diagnose our problems but he did. A couple of calls to the manufacturer and we had a solution. Unfortunately Mark didn’t have…” — Google review
“The technician was on-time, very nice, knowledgeable, did a complete job. He didn't rush it. He showed me what was the problem. I'll definitely recommend him and his company. Im satisfied and happy. Thank you” — Google review
“Great experience. Friendly and efficient team that did a fantastic job. Our septic is working perfectly again. Will definitely use them again.” — Google review
We scan Google Maps for septic tank service listings in and around Rockville, keep only open businesses whose main category matches the service, and require a Google rating of at least 4.5 from at least 20 reviews. Companies are ordered by a confidence-weighted score that balances rating and review volume. We do not accept payment for placement.
Heil Plumbing & HVAC has the highest Google rating on our Rockville list: 5.0 out of 5 from 1,108 reviews (as of November 3, 2026).
Roto-Rooter Plumbing & Water Cleanup has the most Google reviews among the companies listed here: 1,238, with a 4.8★ average.
Only open Rockville-area businesses whose Google category matches the service, rated at least 4.5★ from at least 20 Google reviews. They are ordered by a confidence-weighted score of rating and review volume. Placement is never paid.
Also in Rockville: Kitchen Designers
Analyzing 8,471,0258.5M ReviewsFor 24,07024.1K Experts